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Commit 9802bdd0 authored by Vikram Mulukutla's avatar Vikram Mulukutla Committed by Rishabh Bhatnagar
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firmware: Avoid caching firmware when FW_OPT_NOCACHE is set 



When calling request_firmware_into_buf(), we pass the FW_OPT_NOCACHE
flag with the intent of skipping the caching mechanism of the
firmware loader. Unfortunately, that doesn't work, because
fw_lookup_and_allocate_buf() isn't told to _not_ add the struct
firmware_buf to the firmware cache (fwc) list. So when we call
request_firmware_into_buf() the second time, we find the buffer in
the cache and return it immediately without reloading.

This may break users of request_firmware_into_buf that are expecting
a fresh copy of the firmware to be reloaded into memory. The existing
copy may either be modified by drivers, remote processors or even
freed. Fix fw_lookup_and_allocate_buf to not add to the fwc list
if FW_OPT_NOCACHE is set, and also don't do the lookup in the list.

Fixes: 0e742e9271 ("firmware: provide infrastructure to make fw caching optional")

Change-Id: I39fa4657ab5993b2b8e39ac65000dfc1640db866
Signed-off-by: default avatarVikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: default avatarRishabh Bhatnagar <rishabhb@codeaurora.org>
parent 13c6da45

drivers/base/firmware_loader/main.c

+18 −12
Original line number Diff line number Diff line
@@ -210,11 +210,12 @@ static struct fw_priv *__lookup_fw_priv(const char *fw_name) 
static int alloc_lookup_fw_priv(const char *fw_name,

				struct firmware_cache *fwc,

				struct fw_priv **fw_priv, void *dbuf,

				size_t size)

				size_t size, enum fw_opt opt_flags)

{

	struct fw_priv *tmp;



	spin_lock(&fwc->lock);

	if (!(opt_flags & FW_OPT_NOCACHE)) {

		tmp = __lookup_fw_priv(fw_name);

		if (tmp) {

			kref_get(&tmp->ref);
@@ -223,8 +224,10 @@ static int alloc_lookup_fw_priv(const char *fw_name, 
			pr_debug("batched request - sharing the same struct fw_priv and lookup for multiple requests\n");

			return 1;

		}

	}



	tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size);

	if (tmp)

	if (tmp && !(opt_flags & FW_OPT_NOCACHE))

		list_add(&tmp->list, &fwc->head);

	spin_unlock(&fwc->lock);
@@ -500,7 +503,8 @@ int assign_fw(struct firmware *fw, struct device *device, 
 */

static int

_request_firmware_prepare(struct firmware **firmware_p, const char *name,

			  struct device *device, void *dbuf, size_t size)

			  struct device *device, void *dbuf, size_t size,

			  enum fw_opt opt_flags)

{

	struct firmware *firmware;

	struct fw_priv *fw_priv;
@@ -518,7 +522,8 @@ _request_firmware_prepare(struct firmware **firmware_p, const char *name, 
		return 0; /* assigned */

	}



	ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv, dbuf, size);

	ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv, dbuf, size,

				  opt_flags);



	/*

	 * bind with 'priv' now to avoid warning in failure path
@@ -578,7 +583,8 @@ _request_firmware(const struct firmware **firmware_p, const char *name, 
		goto out;

	}



	ret = _request_firmware_prepare(&fw, name, device, buf, size);

	ret = _request_firmware_prepare(&fw, name, device, buf, size,

					opt_flags);

	if (ret <= 0) /* error or already assigned */

		goto out;