[PATCH] libata: implement ata_dev_id_c_string()

ata_dev_id_c_string() reads ATA string from the specified offset of
the given IDENTIFY PAGE and puts it in the specified buffer in trimmed
and NULL-terminated form.  The caller must supply a buffer which is
one byte larger than the maximum size of the target ID string.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 9ddb568267e1..7e410299d67a 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -519,6 +519,34 @@ void ata_dev_id_string(const u16 *id, unsigned char *s,
         }
 }
 
+/**
+ *      ata_dev_id_c_string - Convert IDENTIFY DEVICE page into C string
+ *      @id: IDENTIFY DEVICE results we will examine
+ *      @s: string into which data is output
+ *      @ofs: offset into identify device page
+ *      @len: length of string to return. must be an odd number.
+ *
+ *      This function is identical to ata_dev_id_string except that it
+ *      trims trailing spaces and terminates the resulting string with
+ *      null.  @len must be actual maximum length (even number) + 1.
+ *
+ *      LOCKING:
+ *      caller.
+ */
+void ata_dev_id_c_string(const u16 *id, unsigned char *s,
+                         unsigned int ofs, unsigned int len)
+{
+        unsigned char *p;
+
+        WARN_ON(!(len & 1));
+
+        ata_dev_id_string(id, s, ofs, len - 1);
+
+        p = s + strnlen(s, len - 1);
+        while (p > s && p[-1] == ' ')
+                p--;
+        *p = '\0';
+}
 
 /**
  *      ata_noop_dev_select - Select device 0/1 on ATA bus
@@ -4905,6 +4933,7 @@ EXPORT_SYMBOL_GPL(ata_scsi_release);
 EXPORT_SYMBOL_GPL(ata_host_intr);
 EXPORT_SYMBOL_GPL(ata_dev_classify);
 EXPORT_SYMBOL_GPL(ata_dev_id_string);
+EXPORT_SYMBOL_GPL(ata_dev_id_c_string);
 EXPORT_SYMBOL_GPL(ata_dev_config);
 EXPORT_SYMBOL_GPL(ata_scsi_simulate);
 EXPORT_SYMBOL_GPL(ata_eh_qc_complete);