Commit 09209006 authored by Adam Wujek's avatar Adam Wujek 💬

arch-wrs: fix commit "improve locking of shmem"

The commit:
15076cb6 arch-wrs: improve locking of shmem
didn't fully apply the patch from the wr-switch repo.
This commit apply changes to arch-wrs/shmem.c that were missed
Signed-off-by: Adam Wujek's avatarAdam Wujek <>
parent 1edcf5c4
......@@ -210,23 +210,27 @@ void wrs_shm_write_caller(void *headptr, int flags, const char *caller)
struct wrs_shm_head *head = headptr;
pr_debug("caller: %s\n", caller);
head->sequence += 2;
pr_debug("caller of a function %s is %s\n", __func__, caller);
if (flags == WRS_SHM_WRITE_BEGIN) {
if (head->sequence & WRS_SHM_LOCK_MASK)
pr_error("Trying to lock already locked shmem on the "
"write end! Sequence number is %d. The caller"
" of wrs_shm_write is %s\n",
head->sequence, caller);
head->sequence |= WRS_SHM_LOCK_MASK;
if (flags == WRS_SHM_WRITE_END) {
/* At end-of-writing update the timestamp too */
head->stamp = get_monotonic_sec();
if (head->sequence & 1)
pr_error("On the shmem write end the sequence number "
"(%d) is even (should be odd). The caller of"
" wrs_shm_write is %s\n",
head->sequence, caller);
} else {
if (!(head->sequence & 1))
pr_error("On the shmem write begin the sequence number"
" (%d) is odd (should be even). The caller of"
" wrs_shm_write is %s\n",
if (!(head->sequence & WRS_SHM_LOCK_MASK))
pr_error("Trying to unlock already unlocked shmem on "
"the write begin! Sequence number is %d. The "
"caller of wrs_shm_write is %s\n",
head->sequence, caller);
head->sequence &= ~WRS_SHM_LOCK_MASK;
......@@ -244,7 +248,7 @@ int wrs_shm_seqretry(void *headptr, unsigned start)
struct wrs_shm_head *head = headptr;
if (start & 1)
if (start & WRS_SHM_LOCK_MASK)
return 1; /* it was odd: retry */
return head->sequence != start;
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