From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read The buffered read collector zero-fills the tail of a short read that stops below the inode's i_size (netfs_clear_unread()), so a read that races an extending write still returns the expected number of bytes. The non-buffered collector path does no such thing: it just records how much was transferred. Add the same zero-fill for the non-buffered case, gated on NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short result from it is known to be safe to treat as a hole, as opposed to NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of the file and should be reported short as-is. Only CLEAR_TAIL should zero-fill here; a real EOF must stay a real short read. No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest, so this is inert on its own -- a following change teaches cifs to set it in the one case that needs it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- drivers/clocksource/clps711x-timer.c | 110 +++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 drivers/clocksource/clps711x-timer.c (limited to 'drivers/clocksource/clps711x-timer.c') diff --git a/drivers/clocksource/clps711x-timer.c b/drivers/clocksource/clps711x-timer.c new file mode 100644 index 000000000..63ae3a691 --- /dev/null +++ b/drivers/clocksource/clps711x-timer.c @@ -0,0 +1,110 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cirrus Logic CLPS711X clocksource driver + * + * Copyright (C) 2014 Alexander Shiyan + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +enum { + CLPS711X_CLKSRC_CLOCKSOURCE, + CLPS711X_CLKSRC_CLOCKEVENT, +}; + +static void __iomem *tcd; + +static u64 notrace clps711x_sched_clock_read(void) +{ + return ~readw(tcd); +} + +static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base) +{ + unsigned long rate = clk_get_rate(clock); + + tcd = base; + + clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16, + clocksource_mmio_readw_down); + + sched_clock_register(clps711x_sched_clock_read, 16, rate); +} + +static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base, + unsigned int irq) +{ + struct clock_event_device *clkevt; + unsigned long rate; + + clkevt = kzalloc_obj(*clkevt); + if (!clkevt) + return -ENOMEM; + + rate = clk_get_rate(clock); + + /* Set Timer prescaler */ + writew(DIV_ROUND_CLOSEST(rate, HZ), base); + + clkevt->name = "clps711x-clockevent"; + clkevt->rating = 300; + clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP; + clkevt->cpumask = cpumask_of(0); + clockevents_config_and_register(clkevt, HZ, 0, 0); + + return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER, + "clps711x-timer", clkevt); +} + +static int __init clps711x_timer_init(struct device_node *np) +{ + unsigned int irq = irq_of_parse_and_map(np, 0); + struct clk *clock = of_clk_get(np, 0); + void __iomem *base = of_iomap(np, 0); + int ret = 0; + + if (!base) + return -ENOMEM; + if (!irq) { + ret = -EINVAL; + goto unmap_io; + } + if (IS_ERR(clock)) { + ret = PTR_ERR(clock); + goto unmap_io; + } + + switch (of_alias_get_id(np, "timer")) { + case CLPS711X_CLKSRC_CLOCKSOURCE: + clps711x_clksrc_init(clock, base); + return 0; + case CLPS711X_CLKSRC_CLOCKEVENT: + ret = _clps711x_clkevt_init(clock, base, irq); + break; + default: + ret = -EINVAL; + break; + } + +unmap_io: + iounmap(base); + return ret; +} +TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init); -- cgit v1.3.1