kmsg - kmsg_dump() use iterator to receive log buffer content

Provide an iterator to receive the log buffer content, and convert all
kmsg_dump() users to it.

The structured data in the kmsg buffer now contains binary data, which
should no longer be copied verbatim to the kmsg_dump() users.

The iterator should provide reliable access to the buffer data, and also
supports proper log line-aware chunking of data while iterating.

Signed-off-by: Kay Sievers <kay@vrfy.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Reported-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Tested-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 18 deletions

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index ae36d7e1e913..551e316e4454 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -304,32 +304,17 @@ static void find_next_position(struct mtdoops_context *cxt)
 }
 
 static void mtdoops_do_dump(struct kmsg_dumper *dumper,
-                enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
-                const char *s2, unsigned long l2)
+                            enum kmsg_dump_reason reason)
 {
         struct mtdoops_context *cxt = container_of(dumper,
                         struct mtdoops_context, dump);
-        unsigned long s1_start, s2_start;
-        unsigned long l1_cpy, l2_cpy;
-        char *dst;
-
-        if (reason != KMSG_DUMP_OOPS &&
-            reason != KMSG_DUMP_PANIC)
-                return;
 
         /* Only dump oopses if dump_oops is set */
         if (reason == KMSG_DUMP_OOPS && !dump_oops)
                 return;
 
-        dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */
-        l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE);
-        l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy);
-
-        s2_start = l2 - l2_cpy;
-        s1_start = l1 - l1_cpy;
-
-        memcpy(dst, s1 + s1_start, l1_cpy);
-        memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
+        kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
+                             record_size - MTDOOPS_HEADER_SIZE, NULL);
 
         /* Panics must be written immediately */
         if (reason != KMSG_DUMP_OOPS)
@@ -375,6 +360,7 @@ static void mtdoops_notify_add(struct mtd_info *mtd)
                 return;
         }
 
+        cxt->dump.max_reason = KMSG_DUMP_OOPS;
         cxt->dump.dump = mtdoops_do_dump;
         err = kmsg_dump_register(&cxt->dump);
         if (err) {