On 12/7/2015 9:12 PM, Russell King wrote:
> Strictly, dma_map_sg() may coalesce SG entries, but in practise on iMX
> hardware, this will never happen. However, dma_map_sg() can fail, and
> we completely fail to check its return value. So, fix this properly.
>
> Arrange the code to map the scatterlist early, so we know how many
> scatter table entries to allocate, and then fill them in. This allows
> us to keep relatively simple error cleanup paths.
>
> Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Some tcrypt tests fail - looks like those with zero plaintext:
caam_jr ffe301000.jr: unable to map source for DMA
alg: hash: digest failed on test 1 for sha1-caam: ret=12
[...]
Need to be careful, dma_map_sg() returning zero is an error only if ptxt
is not null (alternatively src_nents returned by sg_nents_for_len()
could be checked).
> @@ -1091,7 +1102,7 @@ static int ahash_digest(struct ahash_request *req)
> u32 *sh_desc = ctx->sh_desc_digest, *desc;
> dma_addr_t ptr = ctx->sh_desc_digest_dma;
> int digestsize = crypto_ahash_digestsize(ahash);
> - int src_nents, sec4_sg_bytes;
> + int src_nents, mapped_nents, sec4_sg_bytes;
> dma_addr_t src_dma;
> struct ahash_edesc *edesc;
> int ret = 0;
> @@ -1099,9 +1110,14 @@ static int ahash_digest(struct ahash_request *req)
> int sh_len;
>
> src_nents = sg_nents_for_len(req->src, req->nbytes);
> - dma_map_sg(jrdev, req->src, src_nents, DMA_TO_DEVICE);
> - if (src_nents > 1)
> - sec4_sg_bytes = src_nents * sizeof(struct sec4_sg_entry);
> + mapped_nents = dma_map_sg(jrdev, req->src, src_nents, DMA_TO_DEVICE);
> + if (mapped_nents == 0) {
> + dev_err(jrdev, "unable to map source for DMA\n");
> + return -ENOMEM;
> + }
This is at least one of the places where the error condition must change
to smth. like (src_nents != 0 && mapped_nents == 0).
Horia
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