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0018-LU-13783-libcfs-switch-from-mmap_sem-to-mm...
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File 0018-LU-13783-libcfs-switch-from-mmap_sem-to-mmap_lock.patch of Package lustre_2_12
From 2d1ce0f5707b85d5b348eec99a28d128bf7fce31 Mon Sep 17 00:00:00 2001 From: Mr NeilBrown <neilb@suse.de> Date: Fri, 16 Oct 2020 17:18:29 +1100 Subject: [PATCH 18/35] LU-13783 libcfs: switch from ->mmap_sem to mmap_lock() In Linux 5.8, ->mmap_sem is gone and the preferred interface for locking the mmap is to suite of mmap*lock() functions. So provide those functions when not available, and use them as needed in Lustre. Signed-off-by: Mr NeilBrown <neilb@suse.de> Change-Id: I4ce3959f9e93eae10a7b7db03e2b0a1525723138 Reviewed-on: https://review.whamcloud.com/40288 Tested-by: jenkins <devops@whamcloud.com> Tested-by: Maloo <maloo@whamcloud.com> Reviewed-by: James Simmons <jsimmons@infradead.org> Reviewed-by: Andreas Dilger <adilger@whamcloud.com> --- libcfs/autoconf/lustre-libcfs.m4 | 20 +++++++++++ libcfs/include/libcfs/linux/linux-mem.h | 32 +++++++++++++++++ libcfs/libcfs/linux/linux-curproc.c | 8 ++--- lustre/llite/llite_mmap.c | 27 +++++++------- lustre/llite/rw26.c | 4 +-- lustre/llite/vvp_io.c | 48 ++++++++++++------------- 6 files changed, 96 insertions(+), 43 deletions(-) diff --git a/libcfs/autoconf/lustre-libcfs.m4 b/libcfs/autoconf/lustre-libcfs.m4 index c5d31ac92e39..24b1fa6c9d3c 100644 --- a/libcfs/autoconf/lustre-libcfs.m4 +++ b/libcfs/autoconf/lustre-libcfs.m4 @@ -1278,6 +1278,24 @@ nr_unstable_nfs_exists, [ EXTRA_KCFLAGS="$tmp_flags" ]) # LIBCFS_HAVE_NR_UNSTABLE_NFS +# +# LIBCFS_HAVE_MMAP_LOCK +# +# kernel v5.8-rc1~83^2~24 +# mmap locking API: rename mmap_sem to mmap_lock +# +AC_DEFUN([LIBCFS_HAVE_MMAP_LOCK], [ +LB_CHECK_COMPILE([if mmap_lock API is available], +mmap_write_lock, [ + #include <linux/mm.h> +],[ + mmap_write_lock(NULL); +],[ + AC_DEFINE(HAVE_MMAP_LOCK, 1, + [mmap_lock API is available.]) +]) +]) # LIBCFS_HAVE_MMAP_LOCK + # # LIBCFS_PARAM_SET_UINT_MINMAX # @@ -1411,6 +1429,8 @@ LIBCFS_GET_REQUEST_KEY_AUTH LIBCFS_LOOKUP_USER_KEY LIBCFS_CACHE_DETAIL_WRITERS LIBCFS_HAVE_NR_UNSTABLE_NFS +# 5.8 +LIBCFS_HAVE_MMAP_LOCK # 5.15 LIBCFS_PARAM_SET_UINT_MINMAX ]) # LIBCFS_PROG_LINUX diff --git a/libcfs/include/libcfs/linux/linux-mem.h b/libcfs/include/libcfs/linux/linux-mem.h index 6aca65b38a7f..1ae22859ce67 100644 --- a/libcfs/include/libcfs/linux/linux-mem.h +++ b/libcfs/include/libcfs/linux/linux-mem.h @@ -121,4 +121,36 @@ void remove_shrinker(struct shrinker *shrinker) kfree(shrinker); } +#ifndef HAVE_MMAP_LOCK +static inline void mmap_write_lock(struct mm_struct *mm) +{ + down_write(&mm->mmap_sem); +} + +static inline bool mmap_write_trylock(struct mm_struct *mm) +{ + return down_write_trylock(&mm->mmap_sem) != 0; +} + +static inline void mmap_write_unlock(struct mm_struct *mm) +{ + up_write(&mm->mmap_sem); +} + +static inline void mmap_read_lock(struct mm_struct *mm) +{ + down_read(&mm->mmap_sem); +} + +static inline bool mmap_read_trylock(struct mm_struct *mm) +{ + return down_read_trylock(&mm->mmap_sem) != 0; +} + +static inline void mmap_read_unlock(struct mm_struct *mm) +{ + up_read(&mm->mmap_sem); +} +#endif + #endif /* __LINUX_CFS_MEM_H__ */ diff --git a/libcfs/libcfs/linux/linux-curproc.c b/libcfs/libcfs/linux/linux-curproc.c index 8e843a204f39..799c40ea638e 100644 --- a/libcfs/libcfs/linux/linux-curproc.c +++ b/libcfs/libcfs/linux/linux-curproc.c @@ -141,11 +141,11 @@ static int cfs_access_process_vm(struct task_struct *tsk, struct page *page; void *old_buf = buf; - /* Avoid deadlocks on mmap_sem if called from sys_mmap_pgoff(), - * which is already holding mmap_sem for writes. If some other + /* Avoid deadlocks on mmap_lock if called from sys_mmap_pgoff(), + * which is already holding mmap_lock for writes. If some other * thread gets the write lock in the meantime, this thread will * block, but at least it won't deadlock on itself. LU-1735 */ - if (down_read_trylock(&mm->mmap_sem) == 0) + if (!mmap_read_trylock(mm)) return -EDEADLK; /* ignore errors, just check how much was successfully transferred */ @@ -183,7 +183,7 @@ static int cfs_access_process_vm(struct task_struct *tsk, buf += bytes; addr += bytes; } - up_read(&mm->mmap_sem); + mmap_read_unlock(mm); return buf - old_buf; } diff --git a/lustre/llite/llite_mmap.c b/lustre/llite/llite_mmap.c index fee90067a27e..9be9bd690ee6 100644 --- a/lustre/llite/llite_mmap.c +++ b/lustre/llite/llite_mmap.c @@ -54,21 +54,22 @@ void policy_from_vma(union ldlm_policy_data *policy, struct vm_area_struct *vma, struct vm_area_struct *our_vma(struct mm_struct *mm, unsigned long addr, size_t count) { - struct vm_area_struct *vma, *ret = NULL; - ENTRY; + struct vm_area_struct *vma, *ret = NULL; + ENTRY; - /* mmap_sem must have been held by caller. */ - LASSERT(!down_write_trylock(&mm->mmap_sem)); + /* mmap_lock must have been held by caller. */ + LASSERT(!mmap_write_trylock(mm)); - for(vma = find_vma(mm, addr); - vma != NULL && vma->vm_start < (addr + count); vma = vma->vm_next) { - if (vma->vm_ops && vma->vm_ops == &ll_file_vm_ops && - vma->vm_flags & VM_SHARED) { - ret = vma; - break; - } - } - RETURN(ret); + for (vma = find_vma(mm, addr); + vma != NULL && vma->vm_start < (addr + count); + vma = vma->vm_next) { + if (vma->vm_ops && vma->vm_ops == &ll_file_vm_ops && + vma->vm_flags & VM_SHARED) { + ret = vma; + break; + } + } + RETURN(ret); } /** diff --git a/lustre/llite/rw26.c b/lustre/llite/rw26.c index c5a4d4d8172b..9a1f0b6021ba 100644 --- a/lustre/llite/rw26.c +++ b/lustre/llite/rw26.c @@ -453,11 +453,11 @@ static inline int ll_get_user_pages(int rw, unsigned long user_addr, OBD_ALLOC_LARGE(*pages, *max_pages * sizeof(**pages)); if (*pages) { - down_read(¤t->mm->mmap_sem); + mmap_read_lock(current->mm); result = get_user_pages(current, current->mm, user_addr, *max_pages, (rw == READ), 0, *pages, NULL); - up_read(¤t->mm->mmap_sem); + mmap_read_unlock(current->mm); if (unlikely(result <= 0)) OBD_FREE_LARGE(*pages, *max_pages * sizeof(**pages)); } diff --git a/lustre/llite/vvp_io.c b/lustre/llite/vvp_io.c index 8bcc2f469b16..6d8070c5b8bf 100644 --- a/lustre/llite/vvp_io.c +++ b/lustre/llite/vvp_io.c @@ -468,17 +468,17 @@ static int vvp_mmap_locks(const struct lu_env *env, addr = (unsigned long)iov.iov_base; count = iov.iov_len; - if (count == 0) - continue; + if (count == 0) + continue; count += addr & ~PAGE_MASK; addr &= PAGE_MASK; - down_read(&mm->mmap_sem); - while((vma = our_vma(mm, addr, count)) != NULL) { + mmap_read_lock(mm); + while ((vma = our_vma(mm, addr, count)) != NULL) { struct dentry *de = file_dentry(vma->vm_file); struct inode *inode = de->d_inode; - int flags = CEF_MUST; + int flags = CEF_MUST; if (ll_file_nolock(vma->vm_file)) { /* @@ -488,24 +488,24 @@ static int vvp_mmap_locks(const struct lu_env *env, break; } - /* - * XXX: Required lock mode can be weakened: CIT_WRITE - * io only ever reads user level buffer, and CIT_READ - * only writes on it. - */ - policy_from_vma(&policy, vma, addr, count); - descr->cld_mode = vvp_mode_from_vma(vma); - descr->cld_obj = ll_i2info(inode)->lli_clob; - descr->cld_start = cl_index(descr->cld_obj, - policy.l_extent.start); - descr->cld_end = cl_index(descr->cld_obj, - policy.l_extent.end); - descr->cld_enq_flags = flags; - result = cl_io_lock_alloc_add(env, io, descr); - - CDEBUG(D_VFSTRACE, "lock: %d: [%lu, %lu]\n", - descr->cld_mode, descr->cld_start, - descr->cld_end); + /* + * XXX: Required lock mode can be weakened: CIT_WRITE + * io only ever reads user level buffer, and CIT_READ + * only writes on it. + */ + policy_from_vma(&policy, vma, addr, count); + descr->cld_mode = vvp_mode_from_vma(vma); + descr->cld_obj = ll_i2info(inode)->lli_clob; + descr->cld_start = cl_index(descr->cld_obj, + policy.l_extent.start); + descr->cld_end = cl_index(descr->cld_obj, + policy.l_extent.end); + descr->cld_enq_flags = flags; + result = cl_io_lock_alloc_add(env, io, descr); + + CDEBUG(D_VFSTRACE, "lock: %d: [%lu, %lu]\n", + descr->cld_mode, descr->cld_start, + descr->cld_end); if (result < 0) break; @@ -516,7 +516,7 @@ static int vvp_mmap_locks(const struct lu_env *env, count -= vma->vm_end - addr; addr = vma->vm_end; } - up_read(&mm->mmap_sem); + mmap_read_unlock(mm); if (result < 0) break; } -- 2.41.0
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