Commit df9bf19d authored by Kees Cook's avatar Kees Cook
Browse files

pstore/ram: Refactor ftrace buffer merging 

This changes the ftrace record merging code to be agnostic of
pstore/ram, as the first step to making it available as a generic
routine for other backends to use, such as pstore/zone.

Link: https://lore.kernel.org/lkml/20200510202436.63222-6-keescook@chromium.org/


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 26961d76

fs/pstore/ram.c

+17 −12
Original line number Diff line number Diff line
@@ -168,8 +168,9 @@ static bool prz_ok(struct persistent_ram_zone *prz) 
			   persistent_ram_ecc_string(prz, NULL, 0));

}



static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest,

				  struct persistent_ram_zone *src)

static

ssize_t ftrace_log_combine(char **dest_log, size_t *dest_log_size,

			   const char *src_log, size_t src_log_size)

{

	size_t dest_size, src_size, total, dest_off, src_off;

	size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
@@ -177,19 +178,19 @@ static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest, 
	struct pstore_ftrace_record *drec, *srec, *mrec;

	size_t record_size = sizeof(struct pstore_ftrace_record);



	dest_off = dest->old_log_size % record_size;

	dest_size = dest->old_log_size - dest_off;

	dest_off = *dest_log_size % record_size;

	dest_size = *dest_log_size - dest_off;



	src_off = src->old_log_size % record_size;

	src_size = src->old_log_size - src_off;

	src_off = src_log_size % record_size;

	src_size = src_log_size - src_off;



	total = dest_size + src_size;

	merged_buf = kmalloc(total, GFP_KERNEL);

	if (!merged_buf)

		return -ENOMEM;



	drec = (struct pstore_ftrace_record *)(dest->old_log + dest_off);

	srec = (struct pstore_ftrace_record *)(src->old_log + src_off);

	drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);

	srec = (struct pstore_ftrace_record *)(src_log + src_off);

	mrec = (struct pstore_ftrace_record *)(merged_buf);



	while (dest_size > 0 && src_size > 0) {
@@ -213,9 +214,9 @@ static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest, 
		src_size -= record_size;

	}



	kfree(dest->old_log);

	dest->old_log = merged_buf;

	dest->old_log_size = total;

	kfree(*dest_log);

	*dest_log = merged_buf;

	*dest_log_size = total;



	return 0;

}
@@ -291,7 +292,11 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record) 
				tmp_prz->corrected_bytes +=

						prz_next->corrected_bytes;

				tmp_prz->bad_blocks += prz_next->bad_blocks;

				size = ftrace_log_combine(tmp_prz, prz_next);



				size = ftrace_log_combine(&tmp_prz->old_log,

						&tmp_prz->old_log_size,

						prz_next->old_log,

						prz_next->old_log_size);

				if (size)

					goto out;

			}

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