IB/hfi1: Specify mm when releasing pages

This change adds a pointer to the process mm_struct when
calling hfi1_release_user_pages().

Previously, the function used the mm_struct of the current
process to adjust the number of pinned pages. However, is some
cases, namely when unpinning pages due to a MMU notifier call,
we want to drop into that code block as it will cause a deadlock
(the MMU notifiers take the process' mmap_sem prior to calling
the callbacks).

By allowing to caller to specify the pointer to the mm_struct,
the caller has finer control over that part of hfi1_release_user_pages().

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/staging/rdma/hfi1/user_pages.c b/drivers/staging/rdma/hfi1/user_pages.c
index bd7a8ab0d635..88e10b5f55f1 100644
--- a/drivers/staging/rdma/hfi1/user_pages.c
+++ b/drivers/staging/rdma/hfi1/user_pages.c
@@ -116,7 +116,8 @@ int hfi1_acquire_user_pages(unsigned long vaddr, size_t npages, bool writable,
 	return ret;
 }
 
-void hfi1_release_user_pages(struct page **p, size_t npages, bool dirty)
+void hfi1_release_user_pages(struct mm_struct *mm, struct page **p,
+			     size_t npages, bool dirty)
 {
 	size_t i;
 
@@ -126,9 +127,9 @@ void hfi1_release_user_pages(struct page **p, size_t npages, bool dirty)
 		put_page(p[i]);
 	}
 
-	if (current->mm) { /* during close after signal, mm can be NULL */
-		down_write(&current->mm->mmap_sem);
-		current->mm->pinned_vm -= npages;
-		up_write(&current->mm->mmap_sem);
+	if (mm) { /* during close after signal, mm can be NULL */
+		down_write(&mm->mmap_sem);
+		mm->pinned_vm -= npages;
+		up_write(&mm->mmap_sem);
 	}
 }