linux/drivers/block/floppy.c, branch v2.6.19

IRQ: Maintain regs pointer globally rather than passing to IRQ handlers

2006-10-05T14:10:12Z

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

[PATCH] Split struct request ->flags into two parts

2006-09-30T18:23:37Z

Right now ->flags is a bit of a mess: some are request types, and others are just modifiers. Clean this up by splitting it into ->cmd_type and ->cmd_flags. This allows introduction of generic Linux block message types, useful for sending generic Linux commands to block devices. Signed-off-by: Jens Axboe

[PATCH] exit early in floppy_init when no floppy exists

2006-09-01T18:39:08Z

modprobe -v floppy on a Apple G5 writes incorrect stuff to dmesg: Floppy drive(s): fd0 is 2.88M The reason is that the legacy io check happens very late, when part of the floppy stuff is already initialized. check_legacy_ioport() returns either -ENODEV right away, or it walks the device-tree looking for a floppy node. Signed-off-by: Olaf Hering Acked-by: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] lockdep: floppy.c irq release fix

2006-07-03T22:27:00Z

The lock validator triggered a number of bugs in the floppy driver, all related to the floppy driver allocating and freeing irq and dma resources from interrupt context. The initial solution was to use schedule_work() to push this into process context, but this caused further problems: for example the current floppy driver in -mm2 is totally broken and all floppy commands time out with an error. (as reported by Barry K. Nathan) This patch tries another solution: simply get rid of all that dynamic IRQ and DMA allocation/freeing. I doubt it made much sense back in the heydays of floppies (if two devices raced for DMA or IRQ resources then we didnt handle those cases too gracefully anyway), and today it makes near zero sense. So the new code does the simplest and most straightforward thing: allocate IRQ and DMA resources at module init time, and free them at module removal time. Dont try to release while the driver is operational. This, besides making the floppy driver functional again has an added bonus, floppy IRQ stats are finally persistent and visible in /proc/interrupts: 6: 63 XT-PIC-level floppy Besides normal floppy IO i have also tested IO error handling, motor-off timeouts, etc. - and everything seems to be working fine. Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] devfs: Remove the devfs_fs_kernel.h file from the tree

2006-06-26T19:25:08Z

Also fixes up all files that #include it. Signed-off-by: Greg Kroah-Hartman

[PATCH] devfs: Remove devfs_remove() function from the kernel tree

2006-06-26T19:25:07Z

Removes the devfs_remove() function and all callers of it. Signed-off-by: Greg Kroah-Hartman

[PATCH] devfs: Remove devfs_mk_bdev() function from the kernel tree

2006-06-26T19:25:06Z

Removes the devfs_mk_bdev() function and all callers of it. Signed-off-by: Greg Kroah-Hartman

[PATCH] devfs: Remove devfs_mk_dir() function from the kernel tree

2006-06-26T19:25:06Z

Removes the devfs_mk_dir() function and all callers of it. Signed-off-by: Greg Kroah-Hartman

[PATCH] powerpc: Use check_legacy_ioport() on ppc32 too.

2006-04-28T11:04:55Z

Some people report that we die on some Macs when we are expecting to catch machine checks after poking at some random I/O address. I'd seen it happen on my dual G4 with serial ports until we fixed those to use OF, but now other users are reporting it with i8042. This expands the use of check_legacy_ioport() to avoid that situation even on 32-bit kernels. Signed-off-by: David Woodhouse Signed-off-by: Paul Mackerras

[PATCH] drivers/block/*: use time_after() and friends

2006-03-28T17:16:06Z

They deal with wrapping correctly and are nicer to read. Signed-off-by: Marcelo Feitoza Parisi Signed-off-by: Alexey Dobriyan Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds