Re: [PATCH v4] usb: gadget: storage_common: make FSG_NUM_BUFFERSvariable size
From: Michal Nazarewicz
Date: Thu Aug 18 2011 - 08:28:55 EST
On Thu, 18 Aug 2011 11:28:46 +0200, Per Forlin wrote:
diff --git a/drivers/usb/gadget/f_mass_storage.c
b/drivers/usb/gadget/f_mass_storage.c
index 5b93395..3e546d9 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -363,7 +363,6 @@ struct fsg_common {
struct fsg_buffhd *next_buffhd_to_fill;
struct fsg_buffhd *next_buffhd_to_drain;
- struct fsg_buffhd buffhds[FSG_NUM_BUFFERS];
int cmnd_size;
u8 cmnd[MAX_COMMAND_SIZE];
@@ -407,6 +406,8 @@ struct fsg_common {
char inquiry_string[8 + 16 + 4 + 1];
struct kref ref;
+ /* Must be the last entry */
+ struct fsg_buffhd buffhds[0];
I would rather see it as âstruct fsg_buffhd *buffhds;â since this change
requires both mass_storage.c and multi.c to be changed.
Alternatively, revert the possibility for fsg_common_init() to take struct
fsg_common as an argument, but that would be more intrusive I think and
I would prefer the former.
};
struct fsg_config {
@@ -2728,12 +2729,15 @@ static struct fsg_common *fsg_common_init(struct
fsg_common *common,
/* Allocate? */
if (!common) {
- common = kzalloc(sizeof *common, GFP_KERNEL);
+ common = kzalloc(sizeof(struct fsg_common) +
+ sizeof(struct fsg_buffhd) * FSG_NUM_BUFFERS,
+ GFP_KERNEL);
Better yet:
kzalloc(sizeof *common + FSG_NUM_BUFFERS * sizeof *(common->buffhds),
GFP_KERNEL);
but like I've said, I would prefer that buffhds is a separate array.
diff --git a/drivers/usb/gadget/file_storage.c
b/drivers/usb/gadget/file_storage.c
index 639e14a..21d366d 100644
--- a/drivers/usb/gadget/file_storage.c
+++ b/drivers/usb/gadget/file_storage.c
@@ -461,7 +461,6 @@ struct fsg_dev {
struct fsg_buffhd *next_buffhd_to_fill;
struct fsg_buffhd *next_buffhd_to_drain;
- struct fsg_buffhd buffhds[FSG_NUM_BUFFERS];
int thread_wakeup_needed;
struct completion thread_notifier;
@@ -488,6 +487,8 @@ struct fsg_dev {
unsigned int nluns;
struct fsg_lun *luns;
struct fsg_lun *curlun;
+ /* Must be the last entry */
+ struct fsg_buffhd buffhds[0];
IIRC, C99's way of doing it is: âstruct fsg_buffhd buffhds[];â.
};
typedef void (*fsg_routine_t)(struct fsg_dev *);
@@ -3587,7 +3588,9 @@ static int __init fsg_alloc(void)
{
struct fsg_dev *fsg;
- fsg = kzalloc(sizeof *fsg, GFP_KERNEL);
+ fsg = kzalloc(sizeof(struct fsg_dev) +
+ sizeof(struct fsg_buffhd) * FSG_NUM_BUFFERS, GFP_KERNEL);
+
Better yet:
kzalloc(sizeof *fsg + FSG_NUM_BUFFERS * sizeof *(fsg->buffhds),
GFP_KERNEL);
if (!fsg)
return -ENOMEM;
spin_lock_init(&fsg->lock);
diff --git a/drivers/usb/gadget/mass_storage.c
b/drivers/usb/gadget/mass_storage.c
index d3eb274..67c58d0 100644
--- a/drivers/usb/gadget/mass_storage.c
+++ b/drivers/usb/gadget/mass_storage.c
@@ -116,9 +116,8 @@ static int __init msg_do_config(struct
usb_configuration *c)
static const struct fsg_operations ops = {
.thread_exits = msg_thread_exits,
};
- static struct fsg_common common;
+ struct fsg_common *common = NULL;
- struct fsg_common *retp;
struct fsg_config config;
int ret;
@@ -130,12 +129,12 @@ static int __init msg_do_config(struct
usb_configuration *c)
fsg_config_from_params(&config, &mod_data);
config.ops = &ops;
- retp = fsg_common_init(&common, c->cdev, &config);
- if (IS_ERR(retp))
- return PTR_ERR(retp);
+ common = fsg_common_init(common, c->cdev, &config);
The first argument should be NULL.
+ if (IS_ERR(common))
+ return PTR_ERR(common);
- ret = fsg_bind_config(c->cdev, c, &common);
- fsg_common_put(&common);
+ ret = fsg_bind_config(c->cdev, c, common);
+ fsg_common_put(common);
return ret;
}
diff --git a/drivers/usb/gadget/storage_common.c
b/drivers/usb/gadget/storage_common.c
index d3dd227..197eace 100644
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -262,8 +262,24 @@ static struct fsg_lun *fsg_lun_from_dev(struct
device *dev)
#define EP0_BUFSIZE 256
#define DELAYED_STATUS (EP0_BUFSIZE + 999) /* An impossibly large value
*/
-/* Number of buffers we will use. 2 is enough for double-buffering */
-#define FSG_NUM_BUFFERS 2
+#ifdef CONFIG_USB_DEBUG
+
+static unsigned int fsg_num_buffers =
CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
+module_param(fsg_num_buffers, uint, S_IRUGO);
+MODULE_PARM_DESC(fsg_num_buffers, "Number of pipeline buffers");
+#define FSG_NUM_BUFFERS fsg_num_buffers
Could we get rid of the macro all together, and just stick to
âfsg_num_buffersâ variable? Upper case name suggest that it's
a compile time constant which is not true.
+#else
+
+/*
+ * Number of buffers we will use.
+ * 2 is usually enough for good buffering pipeline
+ */
+#define FSG_NUM_BUFFERS CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
Similarly, I'd change the name to lowercase as to reflect that sometimes
it may be not a compile-time constant.
+#endif /* CONFIG_USB_DEBUG */
+#define FSG_NUM_BUFFERS_IS_VALID(num) (num >= 2 && num <= 4 ? true :
false)
The â?:â is not needed.
#define FSG_NUM_BUFFERS_IS_VALID(num) ((num) >= 2 && (num) <= 4)
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michal "mina86" Nazarewicz (o o)
ooo +-----<email/xmpp: mnazarewicz@xxxxxxxxxx>-----ooO--(_)--Ooo--
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