kernel/include/rdma/ib_umem.h, branch linux-3.17.y

IB: ib_umem_release() should decrement mm->pinned_vm from ib_umem_get

2014-09-19T16:55:42Z

In debugging an application that receives -ENOMEM from ib_reg_mr(), I found that ib_umem_get() can fail because the pinned_vm count has wrapped causing it to always be larger than the lock limit even with RLIMIT_MEMLOCK set to RLIM_INFINITY. The wrapping of pinned_vm occurs because the process that calls ib_reg_mr() will have its mm->pinned_vm count incremented. Later a different process with a different mm_struct than the one that allocated the ib_umem struct ends up releasing it which results in decrementing the new processes mm->pinned_vm count past zero and wrapping. I'm not entirely sure what circumstances cause a different process to release the ib_umem than the one that allocated it but the kernel stack trace of the freeing process from my situation looks like the following: Call Trace: [] dump_stack+0x19/0x1b [] ib_umem_release+0x1f5/0x200 [ib_core] [] mlx4_ib_destroy_qp+0x241/0x440 [mlx4_ib] [] ib_destroy_qp+0x12c/0x170 [ib_core] [] ib_uverbs_close+0x259/0x4e0 [ib_uverbs] [] __fput+0xba/0x240 [] ____fput+0xe/0x10 [] task_work_run+0xc4/0xe0 [] do_notify_resume+0x95/0xa0 [] int_signal+0x12/0x17 The following patch fixes the issue by storing the pid struct of the process that calls ib_umem_get() so that ib_umem_release and/or ib_umem_account() can properly decrement the pinned_vm count of the correct mm_struct. Signed-off-by: Shawn Bohrer Reviewed-by: Shachar Raindel Signed-off-by: Roland Dreier

IB: Refactor umem to use linear SG table

2014-03-04T18:34:28Z

This patch refactors the IB core umem code and vendor drivers to use a linear (chained) SG table instead of chunk list. With this change the relevant code becomes clearer—no need for nested loops to build and use umem. Signed-off-by: Shachar Raindel Signed-off-by: Yishai Hadas Signed-off-by: Roland Dreier

IB: expand ib_umem_get() prototype

2008-04-29T15:06:12Z

Add a new parameter, dmasync, to the ib_umem_get() prototype. Use dmasync = 1 when mapping user-allocated CQs with ib_umem_get(). Signed-off-by: Arthur Kepner Cc: Tony Luck Cc: Jesse Barnes Cc: Jes Sorensen Cc: Randy Dunlap Cc: Roland Dreier Cc: James Bottomley Cc: David Miller Cc: Benjamin Herrenschmidt Cc: Grant Grundler Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

IB/umem: Add hugetlb flag to struct ib_umem

2007-10-10T02:59:13Z

During ib_umem_get(), determine whether all pages from the memory region are hugetlb pages and report this in the "hugetlb" member. Low-level drivers can use this information if they need it. Signed-off-by: Joachim Fenkes Signed-off-by: Roland Dreier

Detach sched.h from mm.h

2007-05-21T16:18:19Z

First thing mm.h does is including sched.h solely for can_do_mlock() inline function which has "current" dereference inside. By dealing with can_do_mlock() mm.h can be detached from sched.h which is good. See below, why. This patch a) removes unconditional inclusion of sched.h from mm.h b) makes can_do_mlock() normal function in mm/mlock.c c) exports can_do_mlock() to not break compilation d) adds sched.h inclusions back to files that were getting it indirectly. e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were getting them indirectly Net result is: a) mm.h users would get less code to open, read, preprocess, parse, ... if they don't need sched.h b) sched.h stops being dependency for significant number of files: on x86_64 allmodconfig touching sched.h results in recompile of 4083 files, after patch it's only 3744 (-8.3%). Cross-compile tested on all arm defconfigs, all mips defconfigs, all powerpc defconfigs, alpha alpha-up arm i386 i386-up i386-defconfig i386-allnoconfig ia64 ia64-up m68k mips parisc parisc-up powerpc powerpc-up s390 s390-up sparc sparc-up sparc64 sparc64-up um-x86_64 x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig as well as my two usual configs. Signed-off-by: Alexey Dobriyan Signed-off-by: Linus Torvalds

IB: Put rlimit accounting struct in struct ib_umem

2007-05-09T01:00:37Z

When memory pinned with ib_umem_get() is released, ib_umem_release() needs to subtract the amount of memory being unpinned from mm->locked_vm. However, ib_umem_release() may be called with mm->mmap_sem already held for writing if the memory is being released as part of an munmap() call, so it is sometimes necessary to defer this accounting into a workqueue. However, the work struct used to defer this accounting is dynamically allocated before it is queued, so there is the possibility of failing that allocation. If the allocation fails, then ib_umem_release has no choice except to bail out and leave the process with a permanently elevated locked_vm. Fix this by allocating the structure to defer accounting as part of the original struct ib_umem, so there's no possibility of failing a later allocation if creating the struct ib_umem and pinning memory succeeds. Signed-off-by: Roland Dreier

IB/uverbs: Export ib_umem_get()/ib_umem_release() to modules

2007-05-09T01:00:37Z

Export ib_umem_get()/ib_umem_release() and put low-level drivers in control of when to call ib_umem_get() to pin and DMA map userspace, rather than always calling it in ib_uverbs_reg_mr() before calling the low-level driver's reg_user_mr method. Also move these functions to be in the ib_core module instead of ib_uverbs, so that driver modules using them do not depend on ib_uverbs. This has a number of advantages: - It is better design from the standpoint of making generic code a library that can be used or overridden by device-specific code as the details of specific devices dictate. - Drivers that do not need to pin userspace memory regions do not need to take the performance hit of calling ib_mem_get(). For example, although I have not tried to implement it in this patch, the ipath driver should be able to avoid pinning memory and just use copy_{to,from}_user() to access userspace memory regions. - Buffers that need special mapping treatment can be identified by the low-level driver. For example, it may be possible to solve some Altix-specific memory ordering issues with mthca CQs in userspace by mapping CQ buffers with extra flags. - Drivers that need to pin and DMA map userspace memory for things other than memory regions can use ib_umem_get() directly, instead of hacks using extra parameters to their reg_phys_mr method. For example, the mlx4 driver that is pending being merged needs to pin and DMA map QP and CQ buffers, but it does not need to create a memory key for these buffers. So the cleanest solution is for mlx4 to call ib_umem_get() in the create_qp and create_cq methods. Signed-off-by: Roland Dreier