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Diffstat (limited to 'fs/pstore/platform.c')
-rw-r--r--fs/pstore/platform.c44
1 files changed, 23 insertions, 21 deletions
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 2387cb74f729..2d1066ed3c28 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -161,26 +161,27 @@ static const char *get_reason_str(enum kmsg_dump_reason reason)
}
}
-bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
+/*
+ * Should pstore_dump() wait for a concurrent pstore_dump()? If
+ * not, the current pstore_dump() will report a failure to dump
+ * and return.
+ */
+static bool pstore_cannot_wait(enum kmsg_dump_reason reason)
{
- /*
- * In case of NMI path, pstore shouldn't be blocked
- * regardless of reason.
- */
+ /* In NMI path, pstore shouldn't block regardless of reason. */
if (in_nmi())
return true;
switch (reason) {
/* In panic case, other cpus are stopped by smp_send_stop(). */
case KMSG_DUMP_PANIC:
- /* Emergency restart shouldn't be blocked by spin lock. */
+ /* Emergency restart shouldn't be blocked. */
case KMSG_DUMP_EMERG:
return true;
default:
return false;
}
}
-EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
static int zbufsize_deflate(size_t size)
@@ -400,23 +401,23 @@ static void pstore_dump(struct kmsg_dumper *dumper,
unsigned long total = 0;
const char *why;
unsigned int part = 1;
- unsigned long flags = 0;
- int is_locked;
int ret;
why = get_reason_str(reason);
- if (pstore_cannot_block_path(reason)) {
- is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
- if (!is_locked) {
- pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
- , in_nmi() ? "NMI" : why);
+ if (down_trylock(&psinfo->buf_lock)) {
+ /* Failed to acquire lock: give up if we cannot wait. */
+ if (pstore_cannot_wait(reason)) {
+ pr_err("dump skipped in %s path: may corrupt error record\n",
+ in_nmi() ? "NMI" : why);
+ return;
+ }
+ if (down_interruptible(&psinfo->buf_lock)) {
+ pr_err("could not grab semaphore?!\n");
return;
}
- } else {
- spin_lock_irqsave(&psinfo->buf_lock, flags);
- is_locked = 1;
}
+
oopscount++;
while (total < kmsg_bytes) {
char *dst;
@@ -433,7 +434,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
record.part = part;
record.buf = psinfo->buf;
- if (big_oops_buf && is_locked) {
+ if (big_oops_buf) {
dst = big_oops_buf;
dst_size = big_oops_buf_sz;
} else {
@@ -451,7 +452,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
dst_size, &dump_size))
break;
- if (big_oops_buf && is_locked) {
+ if (big_oops_buf) {
zipped_len = pstore_compress(dst, psinfo->buf,
header_size + dump_size,
psinfo->bufsize);
@@ -474,8 +475,8 @@ static void pstore_dump(struct kmsg_dumper *dumper,
total += record.size;
part++;
}
- if (is_locked)
- spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+
+ up(&psinfo->buf_lock);
}
static struct kmsg_dumper pstore_dumper = {
@@ -594,6 +595,7 @@ int pstore_register(struct pstore_info *psi)
psi->write_user = pstore_write_user_compat;
psinfo = psi;
mutex_init(&psinfo->read_mutex);
+ sema_init(&psinfo->buf_lock, 1);
spin_unlock(&pstore_lock);
if (owner && !try_module_get(owner)) {