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block: sed-opal: split generation of bytestring header and content 

Split the header generation from the (normal) memcpy part if a
bytestring is copied into the command buffer. This allows in-place
generation of the bytestring content. For example, copy_from_user may be
used without an intermediate buffer.

Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
Signed-off-by: David Kozub <zub@linux.fjfi.cvut.cz>
Reviewed-by: Scott Bauer <sbauer@plzdonthack.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jonas Rabenstein 2019-02-14 01:16:02 +01:00 committed by Jens Axboe
parent b2f9c6eb3f
commit 285599590e
1 changed files with 14 additions and 8 deletions
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22
block/sed-opal.c
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@ -580,15 +580,11 @@ static void add_token_u64(int *err, struct opal_dev *cmd, u64 number)
add_token_u8(err, cmd, number >> (len * 8));
}
static void add_token_bytestring(int *err, struct opal_dev *cmd,
const u8 *bytestring, size_t len)
static u8 *add_bytestring_header(int *err, struct opal_dev *cmd, size_t len)
{
size_t header_len = 1;
bool is_short_atom = true;
if (*err)
return;
if (len & ~SHORT_ATOM_LEN_MASK) {
header_len = 2;
is_short_atom = false;
@ -596,7 +592,7 @@ static void add_token_bytestring(int *err, struct opal_dev *cmd,
if (!can_add(err, cmd, header_len + len)) {
pr_debug("Error adding bytestring: end of buffer.\n");
return;
return NULL;
}
if (is_short_atom)
@ -604,9 +600,19 @@ static void add_token_bytestring(int *err, struct opal_dev *cmd,
else
add_medium_atom_header(cmd, true, false, len);
memcpy(&cmd->cmd[cmd->pos], bytestring, len);
cmd->pos += len;
return &cmd->cmd[cmd->pos];
}
static void add_token_bytestring(int *err, struct opal_dev *cmd,
const u8 *bytestring, size_t len)
{
u8 *start;
start = add_bytestring_header(err, cmd, len);
if (!start)
return;
memcpy(start, bytestring, len);
cmd->pos += len;
}
static int build_locking_range(u8 *buffer, size_t length, u8 lr)