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pstore: Refactor compression initialization

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This refactors compression initialization slightly to better handle
getting potentially called twice (via early pstore_register() calls
and later pstore_init()) and improves the comments and reporting to be
more verbose.

Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Guenter Roeck <groeck@chromium.org>
This commit is contained in:
Kees Cook 2018-10-17 14:00:12 -07:00
parent 416031653e
commit 95047b0519
1 changed files with 35 additions and 17 deletions
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52
fs/pstore/platform.c
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@ -274,36 +274,56 @@ static int pstore_decompress(void *in, void *out,
static void allocate_buf_for_compression(void) static void allocate_buf_for_compression(void)
{ {
struct crypto_comp *ctx;
int size;
char *buf;
/* Skip if not built-in or compression backend not selected yet. */
if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend) if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
return; return;
/* Skip if no pstore backend yet or compression init already done. */
if (!psinfo || tfm)
return;
if (!crypto_has_comp(zbackend->name, 0, 0)) { if (!crypto_has_comp(zbackend->name, 0, 0)) {
pr_err("No %s compression\n", zbackend->name); pr_err("Unknown compression: %s\n", zbackend->name);
return; return;
} }
big_oops_buf_sz = zbackend->zbufsize(psinfo->bufsize); size = zbackend->zbufsize(psinfo->bufsize);
if (big_oops_buf_sz <= 0) if (size <= 0) {
return; pr_err("Invalid compression size for %s: %d\n",
zbackend->name, size);
big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
if (!big_oops_buf) {
pr_err("allocate compression buffer error!\n");
return; return;
} }
tfm = crypto_alloc_comp(zbackend->name, 0, 0); buf = kmalloc(size, GFP_KERNEL);
if (IS_ERR_OR_NULL(tfm)) { if (!buf) {
kfree(big_oops_buf); pr_err("Failed %d byte compression buffer allocation for: %s\n",
big_oops_buf = NULL; size, zbackend->name);
pr_err("crypto_alloc_comp() failed!\n");
return; return;
} }
ctx = crypto_alloc_comp(zbackend->name, 0, 0);
if (IS_ERR_OR_NULL(ctx)) {
kfree(buf);
pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
PTR_ERR(ctx));
return;
}
/* A non-NULL big_oops_buf indicates compression is available. */
tfm = ctx;
big_oops_buf_sz = size;
big_oops_buf = buf;
pr_info("Using compression: %s\n", zbackend->name);
} }
static void free_buf_for_compression(void) static void free_buf_for_compression(void)
{ {
if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && !IS_ERR_OR_NULL(tfm)) if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm)
crypto_free_comp(tfm); crypto_free_comp(tfm);
kfree(big_oops_buf); kfree(big_oops_buf);
big_oops_buf = NULL; big_oops_buf = NULL;
@ -774,7 +794,6 @@ void __init pstore_choose_compression(void)
for (step = zbackends; step->name; step++) { for (step = zbackends; step->name; step++) {
if (!strcmp(compress, step->name)) { if (!strcmp(compress, step->name)) {
zbackend = step; zbackend = step;
pr_info("using %s compression\n", zbackend->name);
return; return;
} }
} }
@ -791,8 +810,7 @@ static int __init pstore_init(void)
* initialize compression because crypto was not ready. If so, * initialize compression because crypto was not ready. If so,
* initialize compression now. * initialize compression now.
*/ */
if (psinfo && !tfm) allocate_buf_for_compression();
allocate_buf_for_compression();
ret = pstore_init_fs(); ret = pstore_init_fs();
if (ret) if (ret)