Messages in this thread Patch in this message | | | Date | Fri, 23 Jan 2004 13:32:45 -0500 | From | Glenn Wurster <> | Subject | [PATCH] ide-dma.c, ide.c, ide.h, kernel 2.4.24 |
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Brief Synopsis:
IDE initialization on non-DMA controllers causes OOPS during boot due to dereference of null function pointers.
Description:
This patch fixes an issue where null function pointers associated with DMA are called during initialization of IDE hard drive controllers (causing a kernel OOPS on boot). The problem only occurs on controllers which do not support DMA. It has been tested successfuly against a non-DMA IDE controller on x86.
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Glenn.
diff -Naur linux-2.4.24/drivers/ide/ide-dma.c linux-2.4.24-patched/drivers/ide/ide-dma.c --- linux-2.4.24/drivers/ide/ide-dma.c 2003-08-25 11:44:41.000000000 +0000 +++ linux-2.4.24-patched/drivers/ide/ide-dma.c 2004-01-23 03:23:08.000000000 +0000 @@ -566,6 +566,33 @@ } /** + * __ide_dma_no_op - Empty DMA function. + * + * Empty DMA function for controllers that do not support DMA. + */ + +int __ide_dma_no_op (void) +{ + return 0; +} + +EXPORT_SYMBOL(__ide_dma_no_op); + +/** + * __ide_dma_unsupported - Warning function for DMA operation. + * + * Warning function for DMA operation on unsupported hardware. + */ + +int __ide_dma_unsupported (ide_hwif_t *hwif) +{ + printk(KERN_WARNING "DMA not supported by %s\n", hwif->name ); + return 1; +} + +EXPORT_SYMBOL(__ide_dma_unsupported); + +/** * __ide_dma_host_off - Generic DMA kill * @drive: drive to control * @@ -1214,3 +1241,17 @@ } EXPORT_SYMBOL_GPL(ide_setup_dma); + +/* + * For IDE interfaces that do not support DMA, we still need to + * initialize some pointers to dummy functions during initialization. + */ +void default_hwif_dmaops (ide_hwif_t *hwif) +{ + hwif->ide_dma_on = __ide_dma_unsupported; + hwif->ide_dma_off_quietly = (int (*)(ide_drive_t *))&__ide_dma_no_op; + hwif->ide_dma_host_off = (int (*)(ide_drive_t *))&__ide_dma_no_op; + hwif->ide_dma_host_on = (int (*)(ide_drive_t *))&__ide_dma_no_op; +} + +EXPORT_SYMBOL_GPL(default_hwif_dmaops); diff -Naur linux-2.4.24/drivers/ide/ide.c linux-2.4.24-patched/drivers/ide/ide.c --- linux-2.4.24/drivers/ide/ide.c 2003-11-28 18:26:20.000000000 +0000 +++ linux-2.4.24-patched/drivers/ide/ide.c 2004-01-23 03:32:24.000000000 +0000 @@ -251,6 +251,7 @@ hwif->sata = 0; /* assume PATA */ default_hwif_iops(hwif); + default_hwif_dmaops(hwif); default_hwif_transport(hwif); for (unit = 0; unit < MAX_DRIVES; ++unit) { ide_drive_t *drive = &hwif->drives[unit]; diff -Naur linux-2.4.24/include/linux/ide.h linux-2.4.24-patched/include/linux/ide.h --- linux-2.4.24/include/linux/ide.h 2003-11-28 18:26:21.000000000 +0000 +++ linux-2.4.24-patched/include/linux/ide.h 2004-01-23 03:24:08.000000000 +0000 @@ -1691,8 +1691,12 @@ extern void ide_destroy_dmatable(ide_drive_t *); extern ide_startstop_t ide_dma_intr(ide_drive_t *); extern int ide_release_dma(ide_hwif_t *); +extern void default_hwif_dmaops(ide_hwif_t *); extern void ide_setup_dma(ide_hwif_t *, unsigned long, unsigned int); +extern void ide_setup_dma_off(ide_hwif_t *); +extern int __ide_dma_no_op(void); +extern int __ide_dma_unsupported(ide_hwif_t *); extern int __ide_dma_host_off(ide_drive_t *); extern int __ide_dma_off_quietly(ide_drive_t *); extern int __ide_dma_off(ide_drive_t *); @@ -1712,6 +1716,7 @@ extern int __ide_dma_lostirq(ide_drive_t *); extern int __ide_dma_timeout(ide_drive_t *); #else +static inline void default_hwif_dmaops(ide_hwif_t *x) {;} static inline void ide_setup_dma(ide_hwif_t *x, unsigned long y, unsigned int z) {;} static inline void ide_release_dma(ide_hwif_t *x) {;} #endif - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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