[PATCH v2 09/16] block: sed-opal: split generation of bytestring header and content
From: David Kozub <hidden>
Date: 2019-01-17 21:34:39
Also in:
lkml
Subsystem:
block layer, secure encrypting device (sed) opal driver, the rest · Maintainers:
Jens Axboe, Jonathan Derrick, Linus Torvalds
From: Jonas Rabenstein <redacted> 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 <redacted> --- block/sed-opal.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/block/sed-opal.c b/block/sed-opal.c
index 4225f23b2165..db966bbc5a05 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c@@ -586,14 +586,11 @@ 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; + char *start; if (len & ~SHORT_ATOM_LEN_MASK) { header_len = 2;
@@ -602,17 +599,27 @@ 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) add_short_atom_header(cmd, true, false, len); else add_medium_atom_header(cmd, true, false, len); - - memcpy(&cmd->cmd[cmd->pos], bytestring, len); + start = &cmd->cmd[cmd->pos]; cmd->pos += len; + return start; +} +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); } static int build_locking_range(u8 *buffer, size_t length, u8 lr)
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2.20.1