[dm-devel] [RFC PATCH 02/16] DM: Ability to choose the compressor.
Ram Pai
linuxram at us.ibm.com
Mon Aug 15 17:36:39 UTC 2016
Ability to create a block device with a compression algorithm of the users
choice. Currently lzo and nx842 compressors are supported.
If the compressor algorithm is not specified the default setting in
/sys/modules/dm-inplace-compress/parameters/compress is used.
Signed-off-by: Ram Pai <linuxram at us.ibm.com>
---
drivers/md/dm-inplace-compress.c | 129 ++++++++++++++++++++++++++++----------
drivers/md/dm-inplace-compress.h | 8 ++-
2 files changed, 103 insertions(+), 34 deletions(-)
diff --git a/drivers/md/dm-inplace-compress.c b/drivers/md/dm-inplace-compress.c
index c3c3750..70d6c0e 100644
--- a/drivers/md/dm-inplace-compress.c
+++ b/drivers/md/dm-inplace-compress.c
@@ -20,8 +20,62 @@ static struct dm_icomp_compressor_data compressors[] = {
.name = "lzo",
.comp_len = lzo_comp_len,
},
+ [DMCP_COMP_ALG_842] = {
+ .name = "842",
+ .comp_len = nx842_comp_len,
+ },
+};
+static int default_compressor = -1;
+
+#define DMCP_ALGO_LENGTH 9
+static char dm_icomp_algorithm[DMCP_ALGO_LENGTH] = "lzo";
+static struct kparam_string dm_icomp_compressor_kparam = {
+ .string = dm_icomp_algorithm,
+ .maxlen = sizeof(dm_icomp_algorithm),
};
-static int default_compressor;
+static int dm_icomp_compressor_param_set(const char *,
+ const struct kernel_param *);
+static struct kernel_param_ops dm_icomp_compressor_param_ops = {
+ .set = dm_icomp_compressor_param_set,
+ .get = param_get_string,
+};
+module_param_cb(compress_algorithm, &dm_icomp_compressor_param_ops,
+ &dm_icomp_compressor_kparam, 0644);
+
+static int dm_icomp_get_compressor(const char *s)
+{
+ int r, val_len;
+
+ if (crypto_has_comp(s, 0, 0)) {
+ for (r = 0; r < ARRAY_SIZE(compressors); r++) {
+ val_len = strlen(compressors[r].name);
+ if (strncmp(s, compressors[r].name, val_len) == 0)
+ return r;
+ }
+ }
+ return -1;
+}
+
+static int dm_icomp_compressor_param_set(const char *val,
+ const struct kernel_param *kp)
+{
+ int ret;
+ char str[kp->str->maxlen], *s;
+ int val_len = strlen(val)+1;
+
+ strlcpy(str, val, val_len);
+ s = strim(str);
+ ret = dm_icomp_get_compressor(s);
+ if (ret < 0) {
+ DMWARN("Compressor %s not supported", s);
+ return -1;
+ }
+ DMWARN("compressor is %s", s);
+ default_compressor = ret;
+ strlcpy(dm_icomp_algorithm, compressors[ret].name,
+ sizeof(dm_icomp_algorithm));
+ return 0;
+}
static struct kmem_cache *dm_icomp_req_cachep;
static struct kmem_cache *dm_icomp_io_range_cachep;
@@ -417,7 +471,7 @@ static int dm_icomp_read_or_create_super(struct dm_icomp_info *info)
ret = -EINVAL;
goto out;
}
- if (!crypto_has_comp(compressors[super->comp_alg].name, 0, 0)) {
+ if (!crypto_has_comp(compressors[info->comp_alg].name, 0, 0)) {
info->ti->error =
"Compressor algorithm doesn't support";
ret = -EINVAL;
@@ -436,7 +490,6 @@ static int dm_icomp_read_or_create_super(struct dm_icomp_info *info)
new_super = true;
}
- info->comp_alg = super->comp_alg;
if (dm_icomp_alloc_compressor(info)) {
ret = -ENOMEM;
goto out;
@@ -467,50 +520,56 @@ out:
}
/*
- * <dev> <writethough>/<writeback> <meta_commit_delay>
+ * <dev> [ <writethough>/<writeback> <meta_commit_delay> ]
+ * [ <compressor> <type> ]
*/
static int dm_icomp_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct dm_icomp_info *info;
- char write_mode[15];
+ char mode[15];
+ int par = 0;
int ret, i;
- if (argc < 2) {
- ti->error = "Invalid argument count";
- return -EINVAL;
- }
-
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
ti->error = "dm-inplace-compress: Cannot allocate context";
return -ENOMEM;
}
info->ti = ti;
-
- if (sscanf(argv[1], "%s", write_mode) != 1) {
- ti->error = "Invalid argument";
- ret = -EINVAL;
- goto err_para;
- }
-
- if (strcmp(write_mode, "writeback") == 0) {
- if (argc != 3) {
+ info->comp_alg = default_compressor;
+ while (++par < argc) {
+ if (sscanf(argv[par], "%s", mode) != 1) {
ti->error = "Invalid argument";
ret = -EINVAL;
goto err_para;
}
- info->write_mode = DMCP_WRITE_BACK;
- if (sscanf(argv[2], "%u", &info->writeback_delay) != 1) {
- ti->error = "Invalid argument";
- ret = -EINVAL;
- goto err_para;
+
+ if (strcmp(mode, "writeback") == 0) {
+ info->write_mode = DMCP_WRITE_BACK;
+ if (sscanf(argv[++par], "%u",
+ &info->writeback_delay) != 1) {
+ ti->error = "Invalid argument";
+ ret = -EINVAL;
+ goto err_para;
+ }
+ } else if (strcmp(mode, "writethrough") == 0) {
+ info->write_mode = DMCP_WRITE_THROUGH;
+ } else if (strcmp(mode, "compressor") == 0) {
+ if (sscanf(argv[++par], "%s", mode) != 1) {
+ ti->error = "Invalid argument";
+ ret = -EINVAL;
+ goto err_para;
+ }
+ ret = dm_icomp_get_compressor(mode);
+ if (ret >= 0) {
+ DMWARN("compressor is %s", mode);
+ info->comp_alg = ret;
+ } else {
+ ti->error = "Unsupported compressor";
+ ret = -EINVAL;
+ goto err_para;
+ }
}
- } else if (strcmp(write_mode, "writethrough") == 0) {
- info->write_mode = DMCP_WRITE_THROUGH;
- } else {
- ti->error = "Invalid argument";
- ret = -EINVAL;
- goto err_para;
}
if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
@@ -1407,16 +1466,20 @@ static struct target_type dm_icomp_target = {
static int __init dm_icomp_init(void)
{
int r;
+ int arr_size = ARRAY_SIZE(compressors);
- for (r = 0; r < ARRAY_SIZE(compressors); r++)
+ for (r = 0; r < arr_size; r++)
if (crypto_has_comp(compressors[r].name, 0, 0))
break;
- if (r >= ARRAY_SIZE(compressors)) {
+ if (r >= arr_size) {
DMWARN("No crypto compressors are supported");
return -EINVAL;
}
-
default_compressor = r;
+ strlcpy(dm_icomp_algorithm, compressors[r].name,
+ sizeof(dm_icomp_algorithm));
+ DMWARN(" %s crypto compressor used ",
+ compressors[default_compressor].name);
r = -ENOMEM;
dm_icomp_req_cachep = kmem_cache_create("dm_icomp_requests",
diff --git a/drivers/md/dm-inplace-compress.h b/drivers/md/dm-inplace-compress.h
index e07b9b7..b61ff0d 100644
--- a/drivers/md/dm-inplace-compress.h
+++ b/drivers/md/dm-inplace-compress.h
@@ -10,7 +10,8 @@ struct dm_icomp_super_block {
u8 comp_alg;
} __packed;
-#define DMCP_COMP_ALG_LZO 0
+#define DMCP_COMP_ALG_LZO 1
+#define DMCP_COMP_ALG_842 0
#ifdef __KERNEL__
struct dm_icomp_compressor_data {
@@ -23,6 +24,11 @@ static inline int lzo_comp_len(int comp_len)
return lzo1x_worst_compress(comp_len);
}
+static inline int nx842_comp_len(int comp_len)
+{
+ return comp_len;
+}
+
/*
* Minium logical sector size of this target is 4096 byte, which is a block.
* Data of a block is compressed. Compressed data is round up to 512B, which is
--
1.7.1
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