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74d46992e0
This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
481 lines
12 KiB
C
481 lines
12 KiB
C
/*
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* Xpram.c -- the S/390 expanded memory RAM-disk
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*
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* significant parts of this code are based on
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* the sbull device driver presented in
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* A. Rubini: Linux Device Drivers
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*
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* Author of XPRAM specific coding: Reinhard Buendgen
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* buendgen@de.ibm.com
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* Rewrite for 2.5: Martin Schwidefsky <schwidefsky@de.ibm.com>
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*
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* External interfaces:
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* Interfaces to linux kernel
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* xpram_setup: read kernel parameters
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* Device specific file operations
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* xpram_iotcl
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* xpram_open
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*
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* "ad-hoc" partitioning:
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* the expanded memory can be partitioned among several devices
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* (with different minors). The partitioning set up can be
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* set by kernel or module parameters (int devs & int sizes[])
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*
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* Potential future improvements:
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* generic hard disk support to replace ad-hoc partitioning
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*/
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#define KMSG_COMPONENT "xpram"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/ctype.h> /* isdigit, isxdigit */
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/blkdev.h>
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#include <linux/blkpg.h>
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#include <linux/hdreg.h> /* HDIO_GETGEO */
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#include <linux/device.h>
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#include <linux/bio.h>
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#include <linux/suspend.h>
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#include <linux/platform_device.h>
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#include <linux/gfp.h>
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#include <linux/uaccess.h>
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#define XPRAM_NAME "xpram"
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#define XPRAM_DEVS 1 /* one partition */
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#define XPRAM_MAX_DEVS 32 /* maximal number of devices (partitions) */
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typedef struct {
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unsigned int size; /* size of xpram segment in pages */
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unsigned int offset; /* start page of xpram segment */
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} xpram_device_t;
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static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
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static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
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static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
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static struct request_queue *xpram_queues[XPRAM_MAX_DEVS];
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static unsigned int xpram_pages;
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static int xpram_devs;
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/*
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* Parameter parsing functions.
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*/
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static int devs = XPRAM_DEVS;
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static char *sizes[XPRAM_MAX_DEVS];
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module_param(devs, int, 0);
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module_param_array(sizes, charp, NULL, 0);
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MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
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"the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
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MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
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"the defaults are 0s \n" \
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"All devices with size 0 equally partition the "
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"remaining space on the expanded strorage not "
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"claimed by explicit sizes\n");
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MODULE_LICENSE("GPL");
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/*
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* Copy expanded memory page (4kB) into main memory
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* Arguments
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* page_addr: address of target page
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* xpage_index: index of expandeded memory page
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* Return value
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* 0: if operation succeeds
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* -EIO: if pgin failed
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* -ENXIO: if xpram has vanished
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*/
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static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
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{
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int cc = 2; /* return unused cc 2 if pgin traps */
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asm volatile(
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" .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */
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"0: ipm %0\n"
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" srl %0,28\n"
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"1:\n"
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EX_TABLE(0b,1b)
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: "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
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if (cc == 3)
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return -ENXIO;
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if (cc == 2)
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return -ENXIO;
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if (cc == 1)
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return -EIO;
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return 0;
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}
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/*
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* Copy a 4kB page of main memory to an expanded memory page
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* Arguments
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* page_addr: address of source page
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* xpage_index: index of expandeded memory page
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* Return value
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* 0: if operation succeeds
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* -EIO: if pgout failed
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* -ENXIO: if xpram has vanished
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*/
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static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
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{
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int cc = 2; /* return unused cc 2 if pgin traps */
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asm volatile(
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" .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */
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"0: ipm %0\n"
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" srl %0,28\n"
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"1:\n"
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EX_TABLE(0b,1b)
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: "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
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if (cc == 3)
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return -ENXIO;
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if (cc == 2)
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return -ENXIO;
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if (cc == 1)
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return -EIO;
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return 0;
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}
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/*
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* Check if xpram is available.
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*/
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static int xpram_present(void)
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{
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unsigned long mem_page;
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int rc;
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mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
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if (!mem_page)
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return -ENOMEM;
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rc = xpram_page_in(mem_page, 0);
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free_page(mem_page);
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return rc ? -ENXIO : 0;
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}
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/*
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* Return index of the last available xpram page.
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*/
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static unsigned long xpram_highest_page_index(void)
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{
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unsigned int page_index, add_bit;
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unsigned long mem_page;
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mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
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if (!mem_page)
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return 0;
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page_index = 0;
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add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
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while (add_bit > 0) {
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if (xpram_page_in(mem_page, page_index | add_bit) == 0)
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page_index |= add_bit;
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add_bit >>= 1;
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}
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free_page (mem_page);
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return page_index;
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}
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/*
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* Block device make request function.
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*/
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static blk_qc_t xpram_make_request(struct request_queue *q, struct bio *bio)
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{
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xpram_device_t *xdev = bio->bi_disk->private_data;
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struct bio_vec bvec;
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struct bvec_iter iter;
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unsigned int index;
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unsigned long page_addr;
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unsigned long bytes;
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blk_queue_split(q, &bio);
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if ((bio->bi_iter.bi_sector & 7) != 0 ||
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(bio->bi_iter.bi_size & 4095) != 0)
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/* Request is not page-aligned. */
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goto fail;
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if ((bio->bi_iter.bi_size >> 12) > xdev->size)
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/* Request size is no page-aligned. */
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goto fail;
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if ((bio->bi_iter.bi_sector >> 3) > 0xffffffffU - xdev->offset)
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goto fail;
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index = (bio->bi_iter.bi_sector >> 3) + xdev->offset;
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bio_for_each_segment(bvec, bio, iter) {
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page_addr = (unsigned long)
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kmap(bvec.bv_page) + bvec.bv_offset;
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bytes = bvec.bv_len;
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if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
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/* More paranoia. */
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goto fail;
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while (bytes > 0) {
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if (bio_data_dir(bio) == READ) {
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if (xpram_page_in(page_addr, index) != 0)
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goto fail;
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} else {
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if (xpram_page_out(page_addr, index) != 0)
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goto fail;
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}
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page_addr += 4096;
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bytes -= 4096;
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index++;
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}
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}
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bio_endio(bio);
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return BLK_QC_T_NONE;
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fail:
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bio_io_error(bio);
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return BLK_QC_T_NONE;
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}
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static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
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{
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unsigned long size;
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/*
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* get geometry: we have to fake one... trim the size to a
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* multiple of 64 (32k): tell we have 16 sectors, 4 heads,
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* whatever cylinders. Tell also that data starts at sector. 4.
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*/
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size = (xpram_pages * 8) & ~0x3f;
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geo->cylinders = size >> 6;
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geo->heads = 4;
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geo->sectors = 16;
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geo->start = 4;
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return 0;
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}
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static const struct block_device_operations xpram_devops =
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{
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.owner = THIS_MODULE,
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.getgeo = xpram_getgeo,
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};
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/*
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* Setup xpram_sizes array.
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*/
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static int __init xpram_setup_sizes(unsigned long pages)
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{
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unsigned long mem_needed;
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unsigned long mem_auto;
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unsigned long long size;
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char *sizes_end;
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int mem_auto_no;
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int i;
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/* Check number of devices. */
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if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
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pr_err("%d is not a valid number of XPRAM devices\n",devs);
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return -EINVAL;
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}
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xpram_devs = devs;
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/*
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* Copy sizes array to xpram_sizes and align partition
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* sizes to page boundary.
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*/
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mem_needed = 0;
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mem_auto_no = 0;
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for (i = 0; i < xpram_devs; i++) {
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if (sizes[i]) {
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size = simple_strtoull(sizes[i], &sizes_end, 0);
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switch (*sizes_end) {
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case 'g':
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case 'G':
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size <<= 20;
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break;
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case 'm':
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case 'M':
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size <<= 10;
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}
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xpram_sizes[i] = (size + 3) & -4UL;
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}
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if (xpram_sizes[i])
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mem_needed += xpram_sizes[i];
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else
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mem_auto_no++;
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}
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pr_info(" number of devices (partitions): %d \n", xpram_devs);
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for (i = 0; i < xpram_devs; i++) {
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if (xpram_sizes[i])
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pr_info(" size of partition %d: %u kB\n",
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i, xpram_sizes[i]);
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else
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pr_info(" size of partition %d to be set "
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"automatically\n",i);
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}
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pr_info(" memory needed (for sized partitions): %lu kB\n",
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mem_needed);
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pr_info(" partitions to be sized automatically: %d\n",
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mem_auto_no);
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if (mem_needed > pages * 4) {
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pr_err("Not enough expanded memory available\n");
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return -EINVAL;
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}
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/*
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* partitioning:
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* xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
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* else: ; all partitions with zero xpram_sizes[i]
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* partition equally the remaining space
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*/
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if (mem_auto_no) {
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mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
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pr_info(" automatically determined "
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"partition size: %lu kB\n", mem_auto);
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for (i = 0; i < xpram_devs; i++)
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if (xpram_sizes[i] == 0)
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xpram_sizes[i] = mem_auto;
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}
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return 0;
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}
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static int __init xpram_setup_blkdev(void)
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{
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unsigned long offset;
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int i, rc = -ENOMEM;
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for (i = 0; i < xpram_devs; i++) {
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xpram_disks[i] = alloc_disk(1);
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if (!xpram_disks[i])
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goto out;
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xpram_queues[i] = blk_alloc_queue(GFP_KERNEL);
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if (!xpram_queues[i]) {
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put_disk(xpram_disks[i]);
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goto out;
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}
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queue_flag_set_unlocked(QUEUE_FLAG_NONROT, xpram_queues[i]);
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queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, xpram_queues[i]);
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blk_queue_make_request(xpram_queues[i], xpram_make_request);
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blk_queue_logical_block_size(xpram_queues[i], 4096);
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}
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/*
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* Register xpram major.
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*/
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rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
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if (rc < 0)
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goto out;
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/*
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* Setup device structures.
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*/
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offset = 0;
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for (i = 0; i < xpram_devs; i++) {
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struct gendisk *disk = xpram_disks[i];
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xpram_devices[i].size = xpram_sizes[i] / 4;
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xpram_devices[i].offset = offset;
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offset += xpram_devices[i].size;
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disk->major = XPRAM_MAJOR;
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disk->first_minor = i;
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disk->fops = &xpram_devops;
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disk->private_data = &xpram_devices[i];
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disk->queue = xpram_queues[i];
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sprintf(disk->disk_name, "slram%d", i);
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set_capacity(disk, xpram_sizes[i] << 1);
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add_disk(disk);
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}
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return 0;
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out:
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while (i--) {
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blk_cleanup_queue(xpram_queues[i]);
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put_disk(xpram_disks[i]);
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}
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return rc;
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}
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/*
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* Resume failed: Print error message and call panic.
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*/
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static void xpram_resume_error(const char *message)
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{
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pr_err("Resuming the system failed: %s\n", message);
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panic("xpram resume error\n");
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}
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/*
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* Check if xpram setup changed between suspend and resume.
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*/
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static int xpram_restore(struct device *dev)
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{
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if (!xpram_pages)
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return 0;
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if (xpram_present() != 0)
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xpram_resume_error("xpram disappeared");
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if (xpram_pages != xpram_highest_page_index() + 1)
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xpram_resume_error("Size of xpram changed");
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return 0;
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}
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static const struct dev_pm_ops xpram_pm_ops = {
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.restore = xpram_restore,
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};
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static struct platform_driver xpram_pdrv = {
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.driver = {
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.name = XPRAM_NAME,
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.pm = &xpram_pm_ops,
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},
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};
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static struct platform_device *xpram_pdev;
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/*
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* Finally, the init/exit functions.
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*/
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static void __exit xpram_exit(void)
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{
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int i;
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for (i = 0; i < xpram_devs; i++) {
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del_gendisk(xpram_disks[i]);
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blk_cleanup_queue(xpram_queues[i]);
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put_disk(xpram_disks[i]);
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}
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unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
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platform_device_unregister(xpram_pdev);
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platform_driver_unregister(&xpram_pdrv);
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}
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static int __init xpram_init(void)
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{
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int rc;
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/* Find out size of expanded memory. */
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if (xpram_present() != 0) {
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pr_err("No expanded memory available\n");
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return -ENODEV;
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}
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xpram_pages = xpram_highest_page_index() + 1;
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pr_info(" %u pages expanded memory found (%lu KB).\n",
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xpram_pages, (unsigned long) xpram_pages*4);
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rc = xpram_setup_sizes(xpram_pages);
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if (rc)
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return rc;
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rc = platform_driver_register(&xpram_pdrv);
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if (rc)
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return rc;
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xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0);
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if (IS_ERR(xpram_pdev)) {
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rc = PTR_ERR(xpram_pdev);
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goto fail_platform_driver_unregister;
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}
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rc = xpram_setup_blkdev();
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if (rc)
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goto fail_platform_device_unregister;
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return 0;
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fail_platform_device_unregister:
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platform_device_unregister(xpram_pdev);
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fail_platform_driver_unregister:
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platform_driver_unregister(&xpram_pdrv);
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return rc;
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}
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module_init(xpram_init);
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module_exit(xpram_exit);
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