Commit aae86e8adb3bbf5256eebe76500cf7254365753c
Committed by
Greg Kroah-Hartman
Greg Kroah-Hartman
1 parent
ddb495d4d8
Exists in
master
and in
7 other branches
USB: f_mass_storage: dynamic buffers for better alignment
"Static" buffers in fsg_buffhd structure (ie. fields which are arrays rather then pointers to dynamically allocated memory) are not aligned to any "big" power of two which may lead to poor DMA performance (copying "by hand" of head or tail) or no DMA at all even if otherwise hardware supports it. Therefore, this patch makes mass storage function use kmalloc()ed buffers which are (because of their size) page aligned (which should be enough for any hardware). Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Showing 1 changed file with 18 additions and 5 deletions Side-by-side Diff
drivers/usb/gadget/f_mass_storage.c
| ... | ... | @@ -302,7 +302,6 @@ |
| 302 | 302 | |
| 303 | 303 | |
| 304 | 304 | #define FSG_NO_INTR_EP 1 |
| 305 | -#define FSG_BUFFHD_STATIC_BUFFER 1 | |
| 306 | 305 | #define FSG_NO_DEVICE_STRINGS 1 |
| 307 | 306 | #define FSG_NO_OTG 1 |
| 308 | 307 | #define FSG_NO_INTR_EP 1 |
| 309 | 308 | |
| 310 | 309 | |
| ... | ... | @@ -2762,13 +2761,19 @@ |
| 2762 | 2761 | |
| 2763 | 2762 | |
| 2764 | 2763 | /* Data buffers cyclic list */ |
| 2765 | - /* Buffers in buffhds are static -- no need for additional | |
| 2766 | - * allocation. */ | |
| 2767 | 2764 | bh = common->buffhds; |
| 2768 | - i = FSG_NUM_BUFFERS - 1; | |
| 2765 | + i = FSG_NUM_BUFFERS; | |
| 2766 | + goto buffhds_first_it; | |
| 2769 | 2767 | do { |
| 2770 | 2768 | bh->next = bh + 1; |
| 2771 | - } while (++bh, --i); | |
| 2769 | + ++bh; | |
| 2770 | +buffhds_first_it: | |
| 2771 | + bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL); | |
| 2772 | + if (unlikely(!bh->buf)) { | |
| 2773 | + rc = -ENOMEM; | |
| 2774 | + goto error_release; | |
| 2775 | + } | |
| 2776 | + } while (--i); | |
| 2772 | 2777 | bh->next = common->buffhds; |
| 2773 | 2778 | |
| 2774 | 2779 | |
| ... | ... | @@ -2871,6 +2876,7 @@ |
| 2871 | 2876 | container_of(ref, struct fsg_common, ref); |
| 2872 | 2877 | unsigned i = common->nluns; |
| 2873 | 2878 | struct fsg_lun *lun = common->luns; |
| 2879 | + struct fsg_buffhd *bh; | |
| 2874 | 2880 | |
| 2875 | 2881 | /* If the thread isn't already dead, tell it to exit now */ |
| 2876 | 2882 | if (common->state != FSG_STATE_TERMINATED) { |
| ... | ... | @@ -2892,6 +2898,13 @@ |
| 2892 | 2898 | } |
| 2893 | 2899 | |
| 2894 | 2900 | kfree(common->luns); |
| 2901 | + | |
| 2902 | + i = FSG_NUM_BUFFERS; | |
| 2903 | + bh = common->buffhds; | |
| 2904 | + do { | |
| 2905 | + kfree(bh->buf); | |
| 2906 | + } while (++bh, --i); | |
| 2907 | + | |
| 2895 | 2908 | if (common->free_storage_on_release) |
| 2896 | 2909 | kfree(common); |
| 2897 | 2910 | } |