Patch "IB/hfi1: Reserve user expected TIDs" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    IB/hfi1: Reserve user expected TIDs

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ib-hfi1-reserve-user-expected-tids.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 731e846e5a46c8f3441546e96dfccf617ce2e365
Author: Dean Luick <dean.luick@xxxxxxxxxxxxxxxxxxxx>
Date:   Mon Jan 9 12:31:16 2023 -0500

    IB/hfi1: Reserve user expected TIDs
    
    [ Upstream commit ecf91551cdd2925ed6d9a9d99074fa5f67b90596 ]
    
    To avoid a race, reserve the number of user expected
    TIDs before setup.
    
    Fixes: 7e7a436ecb6e ("staging/hfi1: Add TID entry program function body")
    Signed-off-by: Dean Luick <dean.luick@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/167328547636.1472310.7419712824785353905.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
    Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/infiniband/hw/hfi1/user_exp_rcv.c b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
index 3c609b11e71c..d7487555d109 100644
--- a/drivers/infiniband/hw/hfi1/user_exp_rcv.c
+++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
@@ -282,16 +282,13 @@ int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
 	/* Find sets of physically contiguous pages */
 	tidbuf->n_psets = find_phys_blocks(tidbuf, pinned);
 
-	/*
-	 * We don't need to access this under a lock since tid_used is per
-	 * process and the same process cannot be in hfi1_user_exp_rcv_clear()
-	 * and hfi1_user_exp_rcv_setup() at the same time.
-	 */
+	/* Reserve the number of expected tids to be used. */
 	spin_lock(&fd->tid_lock);
 	if (fd->tid_used + tidbuf->n_psets > fd->tid_limit)
 		pageset_count = fd->tid_limit - fd->tid_used;
 	else
 		pageset_count = tidbuf->n_psets;
+	fd->tid_used += pageset_count;
 	spin_unlock(&fd->tid_lock);
 
 	if (!pageset_count)
@@ -400,10 +397,11 @@ int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
 nomem:
 	hfi1_cdbg(TID, "total mapped: tidpairs:%u pages:%u (%d)", tididx,
 		  mapped_pages, ret);
+	/* adjust reserved tid_used to actual count */
+	spin_lock(&fd->tid_lock);
+	fd->tid_used -= pageset_count - tididx;
+	spin_unlock(&fd->tid_lock);
 	if (tididx) {
-		spin_lock(&fd->tid_lock);
-		fd->tid_used += tididx;
-		spin_unlock(&fd->tid_lock);
 		tinfo->tidcnt = tididx;
 		tinfo->length = mapped_pages * PAGE_SIZE;