On Wed, 11 Mar 2009, Geert Uytterhoeven wrote:
> On Sun, 8 Mar 2009, Phillip Lougher wrote:
> > Two API issues of concern (one major, one minor). Both of these relate to the
> > way Squashfs drives the decompression code, where it repeatedly calls it
> > supplying additional input/output buffers, rather than using a "single-shot"
> > approach where it calls the decompression code once supplying all the
> > necessary input and output buffer space.
> >
> > 1. Minor issue -the lack of a stream.total_out field. The current
> > zlib_inflate code collects the total number of bytes decompressed over the
> > multiple calls into the stream.total_out field.
> >
> > There is clearly no such field available in the cryto API, leading to the
> > somewhat clumsy need to track it, i.e. it leads to the following additional
> > code.
>
> If people feel the need for a total_out field, I can add it to struct
> comp_request.
>
> BTW, what about total_in, which is also provided by plain zlib's z_stream?
> Do people see a need for a similar field?
The patch below (on top of the updated one to convert SquashFS to pcomp) adds
comp_request.total_out, so you don't have to calculate and accumulate the
decompressed output sizes in SquashFS.
Notes:
- This required the addition of a `struct comp_request *' parameter to
crypto_{,de}compress_init()
- Still, there's one of the
produced = req.avail_out;
...
produced -= req.avail_out;
left, as this is part of the logic to discover the end of decompression
(no bytes produced, no error returned).
Perhaps it's better to instead make crypto_{,de}compress_{update,final}()
return the (positive) number of output bytes (of the current step)?
Currently it returns zero (no error) or a negative error value.
That would allow to get rid of both `produced = ... / produced -= ...'
constructs, but the user would have to accumulate the total output size again
(which is not such a big deal, IMHO).
Thanks for your comments!
>From e43f85baa75668be4cce340ae98a3b76e66a452a Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <Geert.Uytterhoeven@xxxxxxxxxxx>
Date: Mon, 16 Mar 2009 15:53:30 +0100
Subject: [PATCH] crypto: compress - Add comp_request.total_out
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@xxxxxxxxxxx>
---
crypto/testmgr.c | 4 ++--
crypto/zlib.c | 12 ++++++++++--
fs/squashfs/block.c | 10 +++-------
include/crypto/compress.h | 17 +++++++++++------
4 files changed, 26 insertions(+), 17 deletions(-)
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index b50c3c6..2b112ae 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -927,7 +927,7 @@ static int test_pcomp(struct crypto_pcomp *tfm,
return error;
}
- error = crypto_compress_init(tfm);
+ error = crypto_compress_init(tfm, &req);
if (error) {
pr_err("alg: pcomp: compression init failed on test "
"%d for %s: error=%d\n", i + 1, algo, error);
@@ -996,7 +996,7 @@ static int test_pcomp(struct crypto_pcomp *tfm,
return error;
}
- error = crypto_decompress_init(tfm);
+ error = crypto_decompress_init(tfm, &req);
if (error) {
pr_err("alg: pcomp: decompression init failed on test "
"%d for %s: error=%d\n", i + 1, algo, error);
diff --git a/crypto/zlib.c b/crypto/zlib.c
index 33609ba..93ec380 100644
--- a/crypto/zlib.c
+++ b/crypto/zlib.c
@@ -125,7 +125,8 @@ static int zlib_compress_setup(struct crypto_pcomp *tfm, void *params,
return 0;
}
-static int zlib_compress_init(struct crypto_pcomp *tfm)
+static int zlib_compress_init(struct crypto_pcomp *tfm,
+ struct comp_request *req)
{
int ret;
struct zlib_ctx *dctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
@@ -135,6 +136,7 @@ static int zlib_compress_init(struct crypto_pcomp *tfm)
if (ret != Z_OK)
return -EINVAL;
+ req->total_out = 0;
return 0;
}
@@ -173,6 +175,7 @@ static int zlib_compress_update(struct crypto_pcomp *tfm,
req->avail_in = stream->avail_in;
req->next_out = stream->next_out;
req->avail_out = stream->avail_out;
+ req->total_out = stream->total_out;
return 0;
}
@@ -203,6 +206,7 @@ static int zlib_compress_final(struct crypto_pcomp *tfm,
req->avail_in = stream->avail_in;
req->next_out = stream->next_out;
req->avail_out = stream->avail_out;
+ req->total_out = stream->total_out;
return 0;
}
@@ -239,7 +243,8 @@ static int zlib_decompress_setup(struct crypto_pcomp *tfm, void *params,
return 0;
}
-static int zlib_decompress_init(struct crypto_pcomp *tfm)
+static int zlib_decompress_init(struct crypto_pcomp *tfm,
+ struct comp_request *req)
{
int ret;
struct zlib_ctx *dctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
@@ -249,6 +254,7 @@ static int zlib_decompress_init(struct crypto_pcomp *tfm)
if (ret != Z_OK)
return -EINVAL;
+ req->total_out = 0;
return 0;
}
@@ -288,6 +294,7 @@ static int zlib_decompress_update(struct crypto_pcomp *tfm,
req->avail_in = stream->avail_in;
req->next_out = stream->next_out;
req->avail_out = stream->avail_out;
+ req->total_out = stream->total_out;
return 0;
}
@@ -336,6 +343,7 @@ static int zlib_decompress_final(struct crypto_pcomp *tfm,
req->avail_in = stream->avail_in;
req->next_out = stream->next_out;
req->avail_out = stream->avail_out;
+ req->total_out = stream->total_out;
return 0;
}
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 6196821..11e19b6 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -168,7 +168,6 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
req.avail_in = 0;
bytes = length;
- length = 0;
do {
if (req.avail_in == 0 && k < b) {
avail = min(bytes, msblk->devblksize - offset);
@@ -194,7 +193,8 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
}
if (!decomp_init) {
- error = crypto_decompress_init(msblk->tfm);
+ error = crypto_decompress_init(msblk->tfm,
+ &req);
if (error) {
ERROR("crypto_decompress_init "
"returned %d, srclength %d\n",
@@ -213,22 +213,18 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
}
produced -= req.avail_out;
- length += produced;
-
if (req.avail_in == 0 && k < b)
put_bh(bh[k++]);
} while (bytes || produced);
- produced = req.avail_out;
error = crypto_decompress_final(msblk->tfm, &req);
if (error) {
ERROR("crypto_decompress_final returned %d, data "
"probably corrupt\n", error);
goto release_mutex;
}
- produced -= req.avail_out;
- length += produced;
+ length = req.total_out;
mutex_unlock(&msblk->read_data_mutex);
} else {
diff --git a/include/crypto/compress.h b/include/crypto/compress.h
index 86163ef..d872c06 100644
--- a/include/crypto/compress.h
+++ b/include/crypto/compress.h
@@ -28,6 +28,7 @@ struct comp_request {
void *next_out; /* next output byte */
unsigned int avail_in; /* bytes available at next_in */
unsigned int avail_out; /* bytes available at next_out */
+ size_t total_out; /* total bytes output so far */
};
enum zlib_comp_params {
@@ -57,14 +58,16 @@ struct crypto_pcomp {
struct pcomp_alg {
int (*compress_setup)(struct crypto_pcomp *tfm, void *params,
unsigned int len);
- int (*compress_init)(struct crypto_pcomp *tfm);
+ int (*compress_init)(struct crypto_pcomp *tfm,
+ struct comp_request *req);
int (*compress_update)(struct crypto_pcomp *tfm,
struct comp_request *req);
int (*compress_final)(struct crypto_pcomp *tfm,
struct comp_request *req);
int (*decompress_setup)(struct crypto_pcomp *tfm, void *params,
unsigned int len);
- int (*decompress_init)(struct crypto_pcomp *tfm);
+ int (*decompress_init)(struct crypto_pcomp *tfm,
+ struct comp_request *req);
int (*decompress_update)(struct crypto_pcomp *tfm,
struct comp_request *req);
int (*decompress_final)(struct crypto_pcomp *tfm,
@@ -102,9 +105,10 @@ static inline int crypto_compress_setup(struct crypto_pcomp *tfm,
return crypto_pcomp_alg(tfm)->compress_setup(tfm, params, len);
}
-static inline int crypto_compress_init(struct crypto_pcomp *tfm)
+static inline int crypto_compress_init(struct crypto_pcomp *tfm,
+ struct comp_request *req)
{
- return crypto_pcomp_alg(tfm)->compress_init(tfm);
+ return crypto_pcomp_alg(tfm)->compress_init(tfm, req);
}
static inline int crypto_compress_update(struct crypto_pcomp *tfm,
@@ -125,9 +129,10 @@ static inline int crypto_decompress_setup(struct crypto_pcomp *tfm,
return crypto_pcomp_alg(tfm)->decompress_setup(tfm, params, len);
}
-static inline int crypto_decompress_init(struct crypto_pcomp *tfm)
+static inline int crypto_decompress_init(struct crypto_pcomp *tfm,
+ struct comp_request *req)
{
- return crypto_pcomp_alg(tfm)->decompress_init(tfm);
+ return crypto_pcomp_alg(tfm)->decompress_init(tfm, req);
}
static inline int crypto_decompress_update(struct crypto_pcomp *tfm,
--
1.6.0.4
With kind regards,
Geert Uytterhoeven
Software Architect
Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium
Phone: +32 (0)2 700 8453
Fax: +32 (0)2 700 8622
E-mail: Geert.Uytterhoeven@xxxxxxxxxxx
Internet: http://www.sony-europe.com/
A division of Sony Europe (Belgium) N.V.
VAT BE 0413.825.160 · RPR Brussels
Fortis · BIC GEBABEBB · IBAN BE41293037680010
--
To unsubscribe from this list: send the line "unsubscribe linux-crypto" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
