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sg_alloc_table_chained() is called by several drivers, but if it is
called before sg_pool_init(), it results in a NULL pointer dereference
in sg_pool_alloc().
Since commit 9b1d6c895002 ("lib: scatterlist: move SG pool code from
SCSI driver to lib/sg_pool.c"), we rely on module_init(sg_pool_init)
is invoked before other module_init calls but this assumption is
fragile.
I slightly changed the link order while refactoring Kbuild, then
uncovered this issue. I should keep the current link order, but
depending on a specific call order among module_init is so fragile.
We usually define the init order by specifying *_initcall correctly,
or delay the driver probing by returning -EPROBE_DEFER.
Change module_initcall() to subsys_initcall(), and also delete the
pointless module_exit() because lib/sg_pool.c is always compiled as
built-in. (CONFIG_SG_POOL is bool)
Link: https://lore.kernel.org/all/[email protected]/
Link: https://lore.kernel.org/all/[email protected]/
Fixes: 9b1d6c895002 ("lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c")
Reported-by: Guenter Roeck <[email protected]>
Reported-by: Marek Szyprowski <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Robin Murphy <[email protected]>
Tested-by: Marek Szyprowski <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
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orig_nents should represent the number of entries with pages,
but __sg_alloc_table_from_pages sets orig_nents as the number of
total entries in the table. This is wrong when the API is used for
dynamic allocation where not all the table entries are mapped with
pages. It wasn't observed until now, since RDMA umem who uses this
API in the dynamic form doesn't use orig_nents implicit or explicit
by the scatterlist APIs.
Fix it by changing the append API to track the SG append table
state and have an API to free the append table according to the
total number of entries in the table.
Now all APIs set orig_nents as number of enries with pages.
Fixes: 07da1223ec93 ("lib/scatterlist: Add support in dynamic allocation of SG table from pages")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Maor Gottlieb <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
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Pull SCSI scatter-gather list updates from James Bottomley:
"This topic branch covers a fundamental change in how our sg lists are
allocated to make mq more efficient by reducing the size of the
preallocated sg list.
This necessitates a large number of driver changes because the
previous guarantee that if a driver specified SG_ALL as the size of
its scatter list, it would get a non-chained list and didn't need to
bother with scatterlist iterators is now broken and every driver
*must* use scatterlist iterators.
This was broken out as a separate topic because we need to convert all
the drivers before pulling the trigger and unconverted drivers kept
being found, necessitating a rebase"
* tag 'scsi-sg' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (21 commits)
scsi: core: don't preallocate small SGL in case of NO_SG_CHAIN
scsi: lib/sg_pool.c: clear 'first_chunk' in case of no preallocation
scsi: core: avoid preallocating big SGL for data
scsi: core: avoid preallocating big SGL for protection information
scsi: lib/sg_pool.c: improve APIs for allocating sg pool
scsi: esp: use sg helper to iterate over scatterlist
scsi: NCR5380: use sg helper to iterate over scatterlist
scsi: wd33c93: use sg helper to iterate over scatterlist
scsi: ppa: use sg helper to iterate over scatterlist
scsi: pcmcia: nsp_cs: use sg helper to iterate over scatterlist
scsi: imm: use sg helper to iterate over scatterlist
scsi: aha152x: use sg helper to iterate over scatterlist
scsi: s390: zfcp_fc: use sg helper to iterate over scatterlist
scsi: staging: unisys: visorhba: use sg helper to iterate over scatterlist
scsi: usb: image: microtek: use sg helper to iterate over scatterlist
scsi: pmcraid: use sg helper to iterate over scatterlist
scsi: ipr: use sg helper to iterate over scatterlist
scsi: mvumi: use sg helper to iterate over scatterlist
scsi: lpfc: use sg helper to iterate over scatterlist
scsi: advansys: use sg helper to iterate over scatterlist
...
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If user doesn't ask to preallocate by passing zero 'nents_first_chunk' to
sg_alloc_table_chained, we need to make sure that 'first_chunk' is cleared.
Otherwise, __sg_alloc_table() still may think that the 1st SGL should be
from the preallocation.
Fixes the issue by clearing 'first_chunk' in sg_alloc_table_chained() if
'nents_first_chunk' is zero.
Cc: Christoph Hellwig <[email protected]>
Cc: Bart Van Assche <[email protected]>
Cc: Ewan D. Milne <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: Guenter Roeck <[email protected]>
Reported-by: Guenter Roeck <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
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sg_alloc_table_chained() currently allows the caller to provide one
preallocated SGL and returns if the requested number isn't bigger than
size of that SGL. This is used to inline an SGL for an IO request.
However, scattergather code only allows that size of the 1st preallocated
SGL to be SG_CHUNK_SIZE(128). This means a substantial amount of memory
(4KB) is claimed for the SGL for each IO request. If the I/O is small, it
would be prudent to allocate a smaller SGL.
Introduce an extra parameter to sg_alloc_table_chained() and
sg_free_table_chained() for specifying size of the preallocated SGL.
Both __sg_free_table() and __sg_alloc_table() assume that each SGL has the
same size except for the last one. Change the code to allow both functions
to accept a variable size for the 1st preallocated SGL.
[mkp: attempted to clarify commit desc]
Cc: Christoph Hellwig <[email protected]>
Cc: Bart Van Assche <[email protected]>
Cc: Ewan D. Milne <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: Sagi Grimberg <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: [email protected]
Cc: [email protected]
Suggested-by: Christoph Hellwig <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
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Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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mempool_destroy(NULL) and kmem_cache_destroy(NULL) are legal
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: zhong jiang <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Now it's ready to move the mempool based SG chained allocator code from
SCSI driver to lib/sg_pool.c, which will be compiled only based on a Kconfig
symbol CONFIG_SG_POOL.
SCSI selects CONFIG_SG_POOL.
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Ming Lin <[email protected]>
Reviewed-by: Sagi Grimberg <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
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