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NVMe: IOCTL path RCU protect queue access

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This adds rcu protected access to a queue in the nvme IOCTL path
to fix potential races between a surprise removal and queue usage in
nvme_submit_sync_cmd. The fix holds the rcu_read_lock() here to prevent
the nvme_queue from freeing while this path is executing so it can't
sleep, and so this path will no longer wait for a available command
id should they all be in use at the time a passthrough IOCTL request
is received.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
This commit is contained in:
Keith Busch 2014-03-03 16:39:13 -07:00 committed by Matthew Wilcox
parent 5a92e700af
commit 4f5099af4f
3 changed files with 60 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

82
drivers/block/nvme-core.c
View File

@ -268,18 +268,30 @@ static struct nvme_queue *raw_nvmeq(struct nvme_dev *dev, int qid)
return rcu_dereference_raw(dev->queues[qid]);
}
struct nvme_queue *get_nvmeq(struct nvme_dev *dev) __acquires(RCU)
static struct nvme_queue *get_nvmeq(struct nvme_dev *dev) __acquires(RCU)
{
rcu_read_lock();
return rcu_dereference(dev->queues[get_cpu() + 1]);
}
void put_nvmeq(struct nvme_queue *nvmeq) __releases(RCU)
static void put_nvmeq(struct nvme_queue *nvmeq) __releases(RCU)
{
put_cpu();
rcu_read_unlock();
}
static struct nvme_queue *lock_nvmeq(struct nvme_dev *dev, int q_idx)
__acquires(RCU)
{
rcu_read_lock();
return rcu_dereference(dev->queues[q_idx]);
}
static void unlock_nvmeq(struct nvme_queue *nvmeq) __releases(RCU)
{
rcu_read_unlock();
}
/**
* nvme_submit_cmd() - Copy a command into a queue and ring the doorbell
* @nvmeq: The queue to use
@ -292,6 +304,10 @@ static int nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
unsigned long flags;
u16 tail;
spin_lock_irqsave(&nvmeq->q_lock, flags);
if (nvmeq->q_suspended) {
spin_unlock_irqrestore(&nvmeq->q_lock, flags);
return -EBUSY;
}
tail = nvmeq->sq_tail;
memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));
if (++tail == nvmeq->q_depth)
@ -812,27 +828,46 @@ static void sync_completion(struct nvme_dev *dev, void *ctx,
* Returns 0 on success. If the result is negative, it's a Linux error code;
* if the result is positive, it's an NVM Express status code
*/
int nvme_submit_sync_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd,
static int nvme_submit_sync_cmd(struct nvme_dev *dev, int q_idx,
struct nvme_command *cmd,
u32 *result, unsigned timeout)
{
int cmdid;
int cmdid, ret;
struct sync_cmd_info cmdinfo;
struct nvme_queue *nvmeq;
nvmeq = lock_nvmeq(dev, q_idx);
if (!nvmeq) {
unlock_nvmeq(nvmeq);
return -ENODEV;
}
cmdinfo.task = current;
cmdinfo.status = -EINTR;
cmdid = alloc_cmdid_killable(nvmeq, &cmdinfo, sync_completion,
timeout);
if (cmdid < 0)
cmdid = alloc_cmdid(nvmeq, &cmdinfo, sync_completion, timeout);
if (cmdid < 0) {
unlock_nvmeq(nvmeq);
return cmdid;
}
cmd->common.command_id = cmdid;
set_current_state(TASK_KILLABLE);
nvme_submit_cmd(nvmeq, cmd);
ret = nvme_submit_cmd(nvmeq, cmd);
if (ret) {
free_cmdid(nvmeq, cmdid, NULL);
unlock_nvmeq(nvmeq);
set_current_state(TASK_RUNNING);
return ret;
}
unlock_nvmeq(nvmeq);
schedule_timeout(timeout);
if (cmdinfo.status == -EINTR) {
nvme_abort_command(nvmeq, cmdid);
nvmeq = lock_nvmeq(dev, q_idx);
if (nvmeq)
nvme_abort_command(nvmeq, cmdid);
unlock_nvmeq(nvmeq);
return -EINTR;
}
@ -853,15 +888,20 @@ static int nvme_submit_async_cmd(struct nvme_queue *nvmeq,
return cmdid;
cmdinfo->status = -EINTR;
cmd->common.command_id = cmdid;
nvme_submit_cmd(nvmeq, cmd);
return 0;
return nvme_submit_cmd(nvmeq, cmd);
}
int nvme_submit_admin_cmd(struct nvme_dev *dev, struct nvme_command *cmd,
u32 *result)
{
return nvme_submit_sync_cmd(raw_nvmeq(dev, 0), cmd, result,
ADMIN_TIMEOUT);
return nvme_submit_sync_cmd(dev, 0, cmd, result, ADMIN_TIMEOUT);
}
int nvme_submit_io_cmd(struct nvme_dev *dev, struct nvme_command *cmd,
u32 *result)
{
return nvme_submit_sync_cmd(dev, smp_processor_id() + 1, cmd, result,
NVME_IO_TIMEOUT);
}
static int nvme_submit_admin_cmd_async(struct nvme_dev *dev,
@ -1434,7 +1474,6 @@ void nvme_unmap_user_pages(struct nvme_dev *dev, int write,
static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
{
struct nvme_dev *dev = ns->dev;
struct nvme_queue *nvmeq;
struct nvme_user_io io;
struct nvme_command c;
unsigned length, meta_len;
@ -1510,20 +1549,10 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
length = nvme_setup_prps(dev, &c.common, iod, length, GFP_KERNEL);
nvmeq = get_nvmeq(dev);
/*
* Since nvme_submit_sync_cmd sleeps, we can't keep preemption
* disabled. We may be preempted at any point, and be rescheduled
* to a different CPU. That will cause cacheline bouncing, but no
* additional races since q_lock already protects against other CPUs.
*/
put_nvmeq(nvmeq);
if (length != (io.nblocks + 1) << ns->lba_shift)
status = -ENOMEM;
else if (!nvmeq || nvmeq->q_suspended)
status = -EBUSY;
else
status = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);
status = nvme_submit_io_cmd(dev, &c, NULL);
if (meta_len) {
if (status == NVME_SC_SUCCESS && !(io.opcode & 1)) {
@ -1597,8 +1626,7 @@ static int nvme_user_admin_cmd(struct nvme_dev *dev,
if (length != cmd.data_len)
status = -ENOMEM;
else
status = nvme_submit_sync_cmd(raw_nvmeq(dev, 0), &c,
&cmd.result, timeout);
status = nvme_submit_sync_cmd(dev, 0, &c, &cmd.result, timeout);
if (cmd.data_len) {
nvme_unmap_user_pages(dev, cmd.opcode & 1, iod);

31
drivers/block/nvme-scsi.c
View File

@ -2033,7 +2033,6 @@ static int nvme_trans_do_nvme_io(struct nvme_ns *ns, struct sg_io_hdr *hdr,
int res = SNTI_TRANSLATION_SUCCESS;
int nvme_sc;
struct nvme_dev *dev = ns->dev;
struct nvme_queue *nvmeq;
u32 num_cmds;
struct nvme_iod *iod;
u64 unit_len;
@ -2106,18 +2105,7 @@ static int nvme_trans_do_nvme_io(struct nvme_ns *ns, struct sg_io_hdr *hdr,
nvme_offset += unit_num_blocks;
nvmeq = get_nvmeq(dev);
/*
* Since nvme_submit_sync_cmd sleeps, we can't keep
* preemption disabled. We may be preempted at any
* point, and be rescheduled to a different CPU. That
* will cause cacheline bouncing, but no additional
* races since q_lock already protects against other
* CPUs.
*/
put_nvmeq(nvmeq);
nvme_sc = nvme_submit_sync_cmd(nvmeq, &c, NULL,
NVME_IO_TIMEOUT);
nvme_sc = nvme_submit_io_cmd(dev, &c, NULL);
if (nvme_sc != NVME_SC_SUCCESS) {
nvme_unmap_user_pages(dev,
(is_write) ? DMA_TO_DEVICE : DMA_FROM_DEVICE,
@ -2644,7 +2632,6 @@ static int nvme_trans_start_stop(struct nvme_ns *ns, struct sg_io_hdr *hdr,
{
int res = SNTI_TRANSLATION_SUCCESS;
int nvme_sc;
struct nvme_queue *nvmeq;
struct nvme_command c;
u8 immed, pcmod, pc, no_flush, start;
@ -2671,10 +2658,7 @@ static int nvme_trans_start_stop(struct nvme_ns *ns, struct sg_io_hdr *hdr,
c.common.opcode = nvme_cmd_flush;
c.common.nsid = cpu_to_le32(ns->ns_id);
nvmeq = get_nvmeq(ns->dev);
put_nvmeq(nvmeq);
nvme_sc = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);
nvme_sc = nvme_submit_io_cmd(ns->dev, &c, NULL);
res = nvme_trans_status_code(hdr, nvme_sc);
if (res)
goto out;
@ -2697,15 +2681,12 @@ static int nvme_trans_synchronize_cache(struct nvme_ns *ns,
int res = SNTI_TRANSLATION_SUCCESS;
int nvme_sc;
struct nvme_command c;
struct nvme_queue *nvmeq;
memset(&c, 0, sizeof(c));
c.common.opcode = nvme_cmd_flush;
c.common.nsid = cpu_to_le32(ns->ns_id);
nvmeq = get_nvmeq(ns->dev);
put_nvmeq(nvmeq);
nvme_sc = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);
nvme_sc = nvme_submit_io_cmd(ns->dev, &c, NULL);
res = nvme_trans_status_code(hdr, nvme_sc);
if (res)
@ -2872,7 +2853,6 @@ static int nvme_trans_unmap(struct nvme_ns *ns, struct sg_io_hdr *hdr,
struct nvme_dev *dev = ns->dev;
struct scsi_unmap_parm_list *plist;
struct nvme_dsm_range *range;
struct nvme_queue *nvmeq;
struct nvme_command c;
int i, nvme_sc, res = -ENOMEM;
u16 ndesc, list_len;
@ -2914,10 +2894,7 @@ static int nvme_trans_unmap(struct nvme_ns *ns, struct sg_io_hdr *hdr,
c.dsm.nr = cpu_to_le32(ndesc - 1);
c.dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);
nvmeq = get_nvmeq(dev);
put_nvmeq(nvmeq);
nvme_sc = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);
nvme_sc = nvme_submit_io_cmd(dev, &c, NULL);
res = nvme_trans_status_code(hdr, nvme_sc);
dma_free_coherent(&dev->pci_dev->dev, ndesc * sizeof(*range),

5
include/linux/nvme.h
View File

@ -151,10 +151,7 @@ struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write,
unsigned long addr, unsigned length);
void nvme_unmap_user_pages(struct nvme_dev *dev, int write,
struct nvme_iod *iod);
struct nvme_queue *get_nvmeq(struct nvme_dev *dev);
void put_nvmeq(struct nvme_queue *nvmeq);
int nvme_submit_sync_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd,
u32 *result, unsigned timeout);
int nvme_submit_io_cmd(struct nvme_dev *, struct nvme_command *, u32 *);
int nvme_submit_flush_data(struct nvme_queue *nvmeq, struct nvme_ns *ns);
int nvme_submit_admin_cmd(struct nvme_dev *, struct nvme_command *,
u32 *result);