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authorDavidlohr Bueso <dave@stgolabs.net>2014-12-12 16:54:30 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-13 12:42:45 -0800
commit4a23717a236b2ab31efb1651f586126789fc997f (patch)
treed7123a21a93fff2ee555d76420504329f371a804 /kernel
parent3dec0ba0be6a532cac949e02b853021bf6d57dad (diff)
downloadblackbird-op-linux-4a23717a236b2ab31efb1651f586126789fc997f.tar.gz
blackbird-op-linux-4a23717a236b2ab31efb1651f586126789fc997f.zip
uprobes: share the i_mmap_rwsem
Both register and unregister call build_map_info() in order to create the list of mappings before installing or removing breakpoints for every mm which maps file backed memory. As such, there is no reason to hold the i_mmap_rwsem exclusively, so share it and allow concurrent readers to build the mapping data. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/uprobes.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 1901dbfa7ce0..995a95f61a19 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -724,7 +724,7 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
int more = 0;
again:
- i_mmap_lock_write(mapping);
+ i_mmap_lock_read(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
if (!valid_vma(vma, is_register))
continue;
@@ -755,7 +755,7 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
info->mm = vma->vm_mm;
info->vaddr = offset_to_vaddr(vma, offset);
}
- i_mmap_unlock_write(mapping);
+ i_mmap_unlock_read(mapping);
if (!more)
goto out;
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