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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: Kees Cook <keescook@chromium.org>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Kees Cook 2018-05-02 16:58:09 -07:00 committed by Martin K. Petersen
parent 66b7eaca54
commit bbe21d7a97
1 changed files with 26 additions and 8 deletions
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34
drivers/scsi/ufs/ufshcd.c
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@ -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;
}