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, 12 insertions, 22 deletions

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 82c585f715e..03ce7a9b81c 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -94,20 +94,15 @@ static const char *get_reason_str(enum kmsg_dump_reason reason)
  * as we can from the end of the buffer.
  */
 static void pstore_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)
 {
-        unsigned long   s1_start, s2_start;
-        unsigned long   l1_cpy, l2_cpy;
-        unsigned long   size, total = 0;
-        char            *dst;
+        unsigned long   total = 0;
         const char      *why;
         u64             id;
-        int             hsize, ret;
         unsigned int    part = 1;
         unsigned long   flags = 0;
         int             is_locked = 0;
+        int             ret;
 
         why = get_reason_str(reason);
 
@@ -119,30 +114,25 @@ static void pstore_dump(struct kmsg_dumper *dumper,
                 spin_lock_irqsave(&psinfo->buf_lock, flags);
         oopscount++;
         while (total < kmsg_bytes) {
+                char *dst;
+                unsigned long size;
+                int hsize;
+                size_t len;
+
                 dst = psinfo->buf;
                 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
                 size = psinfo->bufsize - hsize;
                 dst += hsize;
 
-                l2_cpy = min(l2, size);
-                l1_cpy = min(l1, size - l2_cpy);
-
-                if (l1_cpy + l2_cpy == 0)
+                if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
                         break;
 
-                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);
-
                 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
-                                   hsize + l1_cpy + l2_cpy, psinfo);
+                                    hsize + len, psinfo);
                 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
                         pstore_new_entry = 1;
-                l1 -= l1_cpy;
-                l2 -= l2_cpy;
-                total += l1_cpy + l2_cpy;
+
+                total += hsize + len;
                 part++;
         }
         if (in_nmi()) {