[PATCH v2 26/26] ata: make "libata.force" kernel parameter optional

From: Bartlomiej Zolnierkiewicz
Date: Fri Feb 07 2020 - 09:28:14 EST


Add ATA_FORCE config option (visible only if EXPERT config
option is enabled) and make "libata.force" kernel parameter
optional.

Code size savings on m68k arch using (modified) atari_defconfig:

text data bss dec hex filename
w/ CONFIG_ATA_FORCE=y:
31983 572 40 32595 7f53 drivers/ata/libata-core.o
w/ CONFIG_ATA_FROCE=n:
28958 316 32 29306 727a drivers/ata/libata-core.o

Suggested-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
---
drivers/ata/Kconfig | 16 ++++++++++++++++
drivers/ata/libata-core.c | 22 ++++++++++++++++++++--
drivers/ata/libata.h | 4 ++++
3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 5b55ebf56b5a..05ecdce1b702 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -51,6 +51,22 @@ config ATA_VERBOSE_ERROR

If unsure, say Y.

+config ATA_FORCE
+ bool "\"libata.force=\" kernel parameter support" if EXPERT
+ default y
+ help
+ This option adds support for "libata.force=" kernel parameter for
+ forcing configuration settings.
+
+ For further information, please read
+ <file:Documentation/admin-guide/kernel-parameters.txt>.
+
+ This option will enlarge the kernel by approx. 3KB. Disable it if
+ kernel size is more important than ability to override the default
+ configuration settings.
+
+ If unsure, say Y.
+
config ATA_ACPI
bool "ATA ACPI Support"
depends on ACPI
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 1a3218e81703..fb1bd65acb3c 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -89,6 +89,7 @@ static unsigned long ata_dev_blacklisted(const struct ata_device *dev);

atomic_t ata_print_id = ATOMIC_INIT(0);

+#ifdef CONFIG_ATA_FORCE
struct ata_force_param {
const char *name;
u8 cbl;
@@ -112,6 +113,7 @@ static char ata_force_param_buf[COMMAND_LINE_SIZE] __initdata;
/* param_buf is thrown away after initialization, disallow read */
module_param_string(force, ata_force_param_buf, sizeof(ata_force_param_buf), 0);
MODULE_PARM_DESC(force, "Force ATA configurations including cable type, link speed and transfer mode (see Documentation/admin-guide/kernel-parameters.rst for details)");
+#endif

static int atapi_enabled = 1;
module_param(atapi_enabled, int, 0444);
@@ -303,6 +305,7 @@ struct ata_link *ata_dev_phys_link(struct ata_device *dev)
return ap->slave_link;
}

+#ifdef CONFIG_ATA_FORCE
/**
* ata_force_cbl - force cable type according to libata.force
* @ap: ATA port of interest
@@ -483,6 +486,11 @@ static void ata_force_horkage(struct ata_device *dev)
fe->param.name);
}
}
+#else
+static inline void ata_force_link_limits(struct ata_link *link) { }
+static inline void ata_force_xfermask(struct ata_device *dev) { }
+static inline void ata_force_horkage(struct ata_device *dev) { }
+#endif

/**
* atapi_cmd_type - Determine ATAPI command type from SCSI opcode
@@ -6059,6 +6067,7 @@ int ata_platform_remove_one(struct platform_device *pdev)
}
EXPORT_SYMBOL_GPL(ata_platform_remove_one);

+#ifdef CONFIG_ATA_FORCE
static int __init ata_parse_force_one(char **cur,
struct ata_force_ent *force_ent,
const char **reason)
@@ -6238,6 +6247,15 @@ static void __init ata_parse_force_param(void)
ata_force_tbl_size = idx;
}

+static void ata_free_force_param(void)
+{
+ kfree(ata_force_tbl);
+}
+#else
+static inline void ata_parse_force_param(void) { }
+static inline void ata_free_force_param(void) { }
+#endif
+
static int __init ata_init(void)
{
int rc;
@@ -6246,7 +6264,7 @@ static int __init ata_init(void)

rc = ata_sff_init();
if (rc) {
- kfree(ata_force_tbl);
+ ata_free_force_param();
return rc;
}

@@ -6270,7 +6288,7 @@ static void __exit ata_exit(void)
ata_release_transport(ata_scsi_transport_template);
libata_transport_exit();
ata_sff_exit();
- kfree(ata_force_tbl);
+ ata_free_force_param();
}

subsys_initcall(ata_init);
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 6c808cf39135..68cdd81d747c 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -37,7 +37,11 @@ extern int libata_noacpi;
extern int libata_allow_tpm;
extern const struct device_type ata_port_type;
extern struct ata_link *ata_dev_phys_link(struct ata_device *dev);
+#ifdef CONFIG_ATA_FORCE
extern void ata_force_cbl(struct ata_port *ap);
+#else
+static inline void ata_force_cbl(struct ata_port *ap) { }
+#endif
extern u64 ata_tf_to_lba(const struct ata_taskfile *tf);
extern u64 ata_tf_to_lba48(const struct ata_taskfile *tf);
extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev, int tag);
--
2.24.1