drivers/IB,hfi1: do not se mmap_sem (0e15c253) · Commits · 戴 / test

This driver already uses gup_fast() and thus we can just drop the mmap_sem protection around the pinned_vm counter. Note that the window between when hfi1_can_pin_pages() is called and the actual counter is incremented remains the same as mmap_sem was _only_ used for when ->pinned_vm was touched. Reviewed-by:

Ira Weiny <ira.weiny@intel.com> Signed-off-by:

Davidlohr Bueso <dbueso@suse.det> Signed-off-by:

Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hfi1/user_pages.c

+0 −6

Original line number	Diff line number	Diff line
		@@ -91,9 +91,7 @@ bool hfi1_can_pin_pages(struct hfi1_devdata dd, struct mm_struct mm,
		/* Convert to number of pages */
		size = DIV_ROUND_UP(size, PAGE_SIZE);

		down_read(&mm->mmap_sem);
		pinned = atomic64_read(&mm->pinned_vm);
		up_read(&mm->mmap_sem);

		/* First, check the absolute limit against all pinned pages. */
		if (pinned + npages >= ulimit && !can_lock)
		@@ -111,9 +109,7 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np
		if (ret < 0)
		return ret;

		down_write(&mm->mmap_sem);
		atomic64_add(ret, &mm->pinned_vm);
		up_write(&mm->mmap_sem);

		return ret;
		}
		@@ -130,8 +126,6 @@ void hfi1_release_user_pages(struct mm_struct mm, struct page *p,
		}

		if (mm) { /* during close after signal, mm can be NULL */
		down_write(&mm->mmap_sem);
		atomic64_sub(npages, &mm->pinned_vm);
		up_write(&mm->mmap_sem);
		}
		}

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