Minchan Kim e86942c7b6 zram: handle multiple pages attached bio's bvec ... Patch series "zram clean up", v2. This patchset aims to clean up zram . [1] clean up multiple pages's bvec handling. [2] clean up partial IO handling [3-6] clean up zram via using accessor and removing pointless structure. With [2-6] applied, we can get a few hundred bytes as well as huge readibility enhance. x86: 708 byte save add/remove: 1/1 grow/shrink: 0/11 up/down: 478/-1186 (-708) function old new delta zram_special_page_read - 478 +478 zram_reset_device 317 314 -3 mem_used_max_store 131 128 -3 compact_store 96 93 -3 mm_stat_show 203 197 -6 zram_add 719 712 -7 zram_slot_free_notify 229 214 -15 zram_make_request 819 803 -16 zram_meta_free 128 111 -17 zram_free_page 180 151 -29 disksize_store 432 361 -71 zram_decompress_page.isra 504 - -504 zram_bvec_rw 2592 2080 -512 Total: Before=25350773, After=25350065, chg -0.00% ppc64: 231 byte save add/remove: 2/0 grow/shrink: 1/9 up/down: 681/-912 (-231) function old new delta zram_special_page_read - 480 +480 zram_slot_lock - 200 +200 vermagic 39 40 +1 mm_stat_show 256 248 -8 zram_meta_free 200 184 -16 zram_add 944 912 -32 zram_free_page 348 308 -40 disksize_store 572 492 -80 zram_decompress_page 664 564 -100 zram_slot_free_notify 292 160 -132 zram_make_request 1132 1000 -132 zram_bvec_rw 2768 2396 -372 Total: Before=17565825, After=17565594, chg -0.00% This patch (of 6): Johannes Thumshirn reported system goes the panic when using NVMe over Fabrics loopback target with zram. The reason is zram expects each bvec in bio contains a single page but nvme can attach a huge bulk of pages attached to the bio's bvec so that zram's index arithmetic could be wrong so that out-of-bound access makes system panic. [1] in mainline solved solved the problem by limiting max_sectors with SECTORS_PER_PAGE but it makes zram slow because bio should split with each pages so this patch makes zram aware of multiple pages in a bvec so it could solve without any regression(ie, bio split). [1] 0bc315381f, zram: set physical queue limits to avoid array out of bounds accesses Link: http://lkml.kernel.org/r/20170413134057.GA27499@bbox Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Johannes Thumshirn <jthumshirn@suse.de> Tested-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2017-05-03 15:52:11 -07:00
..
Kconfig	zram: delete custom lzo/lz4	2016-07-26 16:19:19 -07:00
Makefile	zram: delete custom lzo/lz4	2016-07-26 16:19:19 -07:00
zcomp.c	zram: Convert to hotplug state machine	2016-12-02 00:52:39 +01:00
zcomp.h	zram: Convert to hotplug state machine	2016-12-02 00:52:39 +01:00
zram_drv.c	zram: handle multiple pages attached bio's bvec	2017-05-03 15:52:11 -07:00
zram_drv.h	zram: extend zero pages to same element pages	2017-02-24 17:46:56 -08:00