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pstore/ram: Refactor ftrace buffer merging

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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: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2020-05-08 08:34:38 -07:00
parent 26961d76ff
commit df9bf19d88
1 changed files with 17 additions and 12 deletions
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29
fs/pstore/ram.c
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@ -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;
}