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Commit bbe21d7a authored by Kees Cook's avatar Kees Cook Committed by Martin K. Petersen
Browse files

scsi: ufs: ufshcd: Remove VLA usage 

On the quest to remove all VLAs from the kernel[1] this moves buffers
off the stack. In the second instance, this collapses two separately
allocated buffers into a single buffer, since they are used
consecutively, which saves 256 bytes (QUERY_DESC_MAX_SIZE + 1) of stack
space.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com



Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarSubhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 66b7eaca

drivers/scsi/ufs/ufshcd.c

+26 −8
Original line number Diff line number Diff line
@@ -5918,14 +5918,18 @@ static void ufshcd_init_icc_levels(struct ufs_hba *hba) 
{

	int ret;

	int buff_len = hba->desc_size.pwr_desc;

	u8 desc_buf[hba->desc_size.pwr_desc];

	u8 *desc_buf;



	desc_buf = kmalloc(buff_len, GFP_KERNEL);

	if (!desc_buf)

		return;



	ret = ufshcd_read_power_desc(hba, desc_buf, buff_len);

	if (ret) {

		dev_err(hba->dev,

			"%s: Failed reading power descriptor.len = %d ret = %d",

			__func__, buff_len, ret);

		return;

		goto out;

	}



	hba->init_prefetch_data.icc_level =
@@ -5943,6 +5947,8 @@ static void ufshcd_init_icc_levels(struct ufs_hba *hba) 
			"%s: Failed configuring bActiveICCLevel = %d ret = %d",

			__func__, hba->init_prefetch_data.icc_level , ret);



out:

	kfree(desc_buf);

}



/**
@@ -6012,9 +6018,17 @@ static int ufs_get_device_desc(struct ufs_hba *hba, 
			       struct ufs_dev_desc *dev_desc)

{

	int err;

	size_t buff_len;

	u8 model_index;

	u8 str_desc_buf[QUERY_DESC_MAX_SIZE + 1] = {0};

	u8 desc_buf[hba->desc_size.dev_desc];

	u8 *desc_buf;



	buff_len = max_t(size_t, hba->desc_size.dev_desc,

			 QUERY_DESC_MAX_SIZE + 1);

	desc_buf = kmalloc(buff_len, GFP_KERNEL);

	if (!desc_buf) {

		err = -ENOMEM;

		goto out;

	}



	err = ufshcd_read_device_desc(hba, desc_buf, hba->desc_size.dev_desc);

	if (err) {
@@ -6032,7 +6046,10 @@ static int ufs_get_device_desc(struct ufs_hba *hba, 


	model_index = desc_buf[DEVICE_DESC_PARAM_PRDCT_NAME];



	err = ufshcd_read_string_desc(hba, model_index, str_desc_buf,

	/* Zero-pad entire buffer for string termination. */

	memset(desc_buf, 0, buff_len);



	err = ufshcd_read_string_desc(hba, model_index, desc_buf,

				      QUERY_DESC_MAX_SIZE, true/*ASCII*/);

	if (err) {

		dev_err(hba->dev, "%s: Failed reading Product Name. err = %d\n",
@@ -6040,15 +6057,16 @@ static int ufs_get_device_desc(struct ufs_hba *hba, 
		goto out;

	}



	str_desc_buf[QUERY_DESC_MAX_SIZE] = '\0';

	strlcpy(dev_desc->model, (str_desc_buf + QUERY_DESC_HDR_SIZE),

		min_t(u8, str_desc_buf[QUERY_DESC_LENGTH_OFFSET],

	desc_buf[QUERY_DESC_MAX_SIZE] = '\0';

	strlcpy(dev_desc->model, (desc_buf + QUERY_DESC_HDR_SIZE),

		min_t(u8, desc_buf[QUERY_DESC_LENGTH_OFFSET],

		      MAX_MODEL_LEN));



	/* Null terminate the model string */

	dev_desc->model[MAX_MODEL_LEN] = '\0';



out:

	kfree(desc_buf);

	return err;

}