netfs: zero the tail of a short DIO/unbuffered readgrafted

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 <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org

1 files changed, 306 insertions, 0 deletions

diff --git a/drivers/bcma/driver_pci.c b/drivers/bcma/driver_pci.c
new file mode 100644
index 000000000..12b2cc9a3
--- /dev/null
+++ b/drivers/bcma/driver_pci.c
@@ -0,0 +1,306 @@
+/*
+ * Broadcom specific AMBA
+ * PCI Core
+ *
+ * Copyright 2005, 2011, Broadcom Corporation
+ * Copyright 2006, 2007, Michael Buesch <m@bues.ch>
+ * Copyright 2011, 2012, Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include "bcma_private.h"
+#include <linux/export.h>
+#include <linux/bcma/bcma.h>
+
+/**************************************************
+ * R/W ops.
+ **************************************************/
+
+u32 bcma_pcie_read(struct bcma_drv_pci *pc, u32 address)
+{
+	pcicore_write32(pc, BCMA_CORE_PCI_PCIEIND_ADDR, address);
+	pcicore_read32(pc, BCMA_CORE_PCI_PCIEIND_ADDR);
+	return pcicore_read32(pc, BCMA_CORE_PCI_PCIEIND_DATA);
+}
+
+static void bcma_pcie_write(struct bcma_drv_pci *pc, u32 address, u32 data)
+{
+	pcicore_write32(pc, BCMA_CORE_PCI_PCIEIND_ADDR, address);
+	pcicore_read32(pc, BCMA_CORE_PCI_PCIEIND_ADDR);
+	pcicore_write32(pc, BCMA_CORE_PCI_PCIEIND_DATA, data);
+}
+
+static void bcma_pcie_mdio_set_phy(struct bcma_drv_pci *pc, u16 phy)
+{
+	u32 v;
+	int i;
+
+	v = BCMA_CORE_PCI_MDIODATA_START;
+	v |= BCMA_CORE_PCI_MDIODATA_WRITE;
+	v |= (BCMA_CORE_PCI_MDIODATA_DEV_ADDR <<
+	      BCMA_CORE_PCI_MDIODATA_DEVADDR_SHF);
+	v |= (BCMA_CORE_PCI_MDIODATA_BLK_ADDR <<
+	      BCMA_CORE_PCI_MDIODATA_REGADDR_SHF);
+	v |= BCMA_CORE_PCI_MDIODATA_TA;
+	v |= (phy << 4);
+	pcicore_write32(pc, BCMA_CORE_PCI_MDIO_DATA, v);
+
+	udelay(10);
+	for (i = 0; i < 200; i++) {
+		v = pcicore_read32(pc, BCMA_CORE_PCI_MDIO_CONTROL);
+		if (v & BCMA_CORE_PCI_MDIOCTL_ACCESS_DONE)
+			break;
+		usleep_range(1000, 2000);
+	}
+}
+
+static u16 bcma_pcie_mdio_read(struct bcma_drv_pci *pc, u16 device, u8 address)
+{
+	int max_retries = 10;
+	u16 ret = 0;
+	u32 v;
+	int i;
+
+	/* enable mdio access to SERDES */
+	v = BCMA_CORE_PCI_MDIOCTL_PREAM_EN;
+	v |= BCMA_CORE_PCI_MDIOCTL_DIVISOR_VAL;
+	pcicore_write32(pc, BCMA_CORE_PCI_MDIO_CONTROL, v);
+
+	if (pc->core->id.rev >= 10) {
+		max_retries = 200;
+		bcma_pcie_mdio_set_phy(pc, device);
+		v = (BCMA_CORE_PCI_MDIODATA_DEV_ADDR <<
+		     BCMA_CORE_PCI_MDIODATA_DEVADDR_SHF);
+		v |= (address << BCMA_CORE_PCI_MDIODATA_REGADDR_SHF);
+	} else {
+		v = (device << BCMA_CORE_PCI_MDIODATA_DEVADDR_SHF_OLD);
+		v |= (address << BCMA_CORE_PCI_MDIODATA_REGADDR_SHF_OLD);
+	}
+
+	v |= BCMA_CORE_PCI_MDIODATA_START;
+	v |= BCMA_CORE_PCI_MDIODATA_READ;
+	v |= BCMA_CORE_PCI_MDIODATA_TA;
+
+	pcicore_write32(pc, BCMA_CORE_PCI_MDIO_DATA, v);
+	/* Wait for the device to complete the transaction */
+	udelay(10);
+	for (i = 0; i < max_retries; i++) {
+		v = pcicore_read32(pc, BCMA_CORE_PCI_MDIO_CONTROL);
+		if (v & BCMA_CORE_PCI_MDIOCTL_ACCESS_DONE) {
+			udelay(10);
+			ret = pcicore_read32(pc, BCMA_CORE_PCI_MDIO_DATA);
+			break;
+		}
+		usleep_range(1000, 2000);
+	}
+	pcicore_write32(pc, BCMA_CORE_PCI_MDIO_CONTROL, 0);
+	return ret;
+}
+
+static void bcma_pcie_mdio_write(struct bcma_drv_pci *pc, u16 device,
+				u8 address, u16 data)
+{
+	int max_retries = 10;
+	u32 v;
+	int i;
+
+	/* enable mdio access to SERDES */
+	v = BCMA_CORE_PCI_MDIOCTL_PREAM_EN;
+	v |= BCMA_CORE_PCI_MDIOCTL_DIVISOR_VAL;
+	pcicore_write32(pc, BCMA_CORE_PCI_MDIO_CONTROL, v);
+
+	if (pc->core->id.rev >= 10) {
+		max_retries = 200;
+		bcma_pcie_mdio_set_phy(pc, device);
+		v = (BCMA_CORE_PCI_MDIODATA_DEV_ADDR <<
+		     BCMA_CORE_PCI_MDIODATA_DEVADDR_SHF);
+		v |= (address << BCMA_CORE_PCI_MDIODATA_REGADDR_SHF);
+	} else {
+		v = (device << BCMA_CORE_PCI_MDIODATA_DEVADDR_SHF_OLD);
+		v |= (address << BCMA_CORE_PCI_MDIODATA_REGADDR_SHF_OLD);
+	}
+
+	v |= BCMA_CORE_PCI_MDIODATA_START;
+	v |= BCMA_CORE_PCI_MDIODATA_WRITE;
+	v |= BCMA_CORE_PCI_MDIODATA_TA;
+	v |= data;
+	pcicore_write32(pc, BCMA_CORE_PCI_MDIO_DATA, v);
+	/* Wait for the device to complete the transaction */
+	udelay(10);
+	for (i = 0; i < max_retries; i++) {
+		v = pcicore_read32(pc, BCMA_CORE_PCI_MDIO_CONTROL);
+		if (v & BCMA_CORE_PCI_MDIOCTL_ACCESS_DONE)
+			break;
+		usleep_range(1000, 2000);
+	}
+	pcicore_write32(pc, BCMA_CORE_PCI_MDIO_CONTROL, 0);
+}
+
+static u16 bcma_pcie_mdio_writeread(struct bcma_drv_pci *pc, u16 device,
+				    u8 address, u16 data)
+{
+	bcma_pcie_mdio_write(pc, device, address, data);
+	return bcma_pcie_mdio_read(pc, device, address);
+}
+
+/**************************************************
+ * Early init.
+ **************************************************/
+
+static void bcma_core_pci_fixcfg(struct bcma_drv_pci *pc)
+{
+	struct bcma_device *core = pc->core;
+	u16 val16, core_index;
+	uint regoff;
+
+	regoff = BCMA_CORE_PCI_SPROM(BCMA_CORE_PCI_SPROM_PI_OFFSET);
+	core_index = (u16)core->core_index;
+
+	val16 = pcicore_read16(pc, regoff);
+	if (((val16 & BCMA_CORE_PCI_SPROM_PI_MASK) >> BCMA_CORE_PCI_SPROM_PI_SHIFT)
+	     != core_index) {
+		val16 = (core_index << BCMA_CORE_PCI_SPROM_PI_SHIFT) |
+			(val16 & ~BCMA_CORE_PCI_SPROM_PI_MASK);
+		pcicore_write16(pc, regoff, val16);
+	}
+}
+
+/*
+ * Apply some early fixes required before accessing SPROM.
+ * See also si_pci_fixcfg.
+ */
+void bcma_core_pci_early_init(struct bcma_drv_pci *pc)
+{
+	if (pc->early_setup_done)
+		return;
+
+	pc->hostmode = bcma_core_pci_is_in_hostmode(pc);
+	if (pc->hostmode)
+		goto out;
+
+	bcma_core_pci_fixcfg(pc);
+
+out:
+	pc->early_setup_done = true;
+}
+
+/**************************************************
+ * Workarounds.
+ **************************************************/
+
+static u8 bcma_pcicore_polarity_workaround(struct bcma_drv_pci *pc)
+{
+	u32 tmp;
+
+	tmp = bcma_pcie_read(pc, BCMA_CORE_PCI_PLP_STATUSREG);
+	if (tmp & BCMA_CORE_PCI_PLP_POLARITYINV_STAT)
+		return BCMA_CORE_PCI_SERDES_RX_CTRL_FORCE |
+		       BCMA_CORE_PCI_SERDES_RX_CTRL_POLARITY;
+	else
+		return BCMA_CORE_PCI_SERDES_RX_CTRL_FORCE;
+}
+
+static void bcma_pcicore_serdes_workaround(struct bcma_drv_pci *pc)
+{
+	u16 tmp;
+
+	bcma_pcie_mdio_write(pc, BCMA_CORE_PCI_MDIODATA_DEV_RX,
+	                     BCMA_CORE_PCI_SERDES_RX_CTRL,
+			     bcma_pcicore_polarity_workaround(pc));
+	tmp = bcma_pcie_mdio_read(pc, BCMA_CORE_PCI_MDIODATA_DEV_PLL,
+	                          BCMA_CORE_PCI_SERDES_PLL_CTRL);
+	if (tmp & BCMA_CORE_PCI_PLL_CTRL_FREQDET_EN)
+		bcma_pcie_mdio_write(pc, BCMA_CORE_PCI_MDIODATA_DEV_PLL,
+		                     BCMA_CORE_PCI_SERDES_PLL_CTRL,
+		                     tmp & ~BCMA_CORE_PCI_PLL_CTRL_FREQDET_EN);
+}
+
+/* Fix MISC config to allow coming out of L2/L3-Ready state w/o PRST */
+/* Needs to happen when coming out of 'standby'/'hibernate' */
+static void bcma_core_pci_config_fixup(struct bcma_drv_pci *pc)
+{
+	u16 val16;
+	uint regoff;
+
+	regoff = BCMA_CORE_PCI_SPROM(BCMA_CORE_PCI_SPROM_MISC_CONFIG);
+
+	val16 = pcicore_read16(pc, regoff);
+
+	if (!(val16 & BCMA_CORE_PCI_SPROM_L23READY_EXIT_NOPERST)) {
+		val16 |= BCMA_CORE_PCI_SPROM_L23READY_EXIT_NOPERST;
+		pcicore_write16(pc, regoff, val16);
+	}
+}
+
+/**************************************************
+ * Init.
+ **************************************************/
+
+static void bcma_core_pci_clientmode_init(struct bcma_drv_pci *pc)
+{
+	bcma_pcicore_serdes_workaround(pc);
+	bcma_core_pci_config_fixup(pc);
+}
+
+void bcma_core_pci_init(struct bcma_drv_pci *pc)
+{
+	if (pc->setup_done)
+		return;
+
+	bcma_core_pci_early_init(pc);
+
+	if (pc->hostmode)
+		bcma_core_pci_hostmode_init(pc);
+	else
+		bcma_core_pci_clientmode_init(pc);
+}
+
+void bcma_core_pci_power_save(struct bcma_bus *bus, bool up)
+{
+	struct bcma_drv_pci *pc;
+	u16 data;
+
+	if (bus->hosttype != BCMA_HOSTTYPE_PCI)
+		return;
+
+	pc = &bus->drv_pci[0];
+
+	if (pc->core->id.rev >= 15 && pc->core->id.rev <= 20) {
+		data = up ? 0x74 : 0x7C;
+		bcma_pcie_mdio_writeread(pc, BCMA_CORE_PCI_MDIO_BLK1,
+					 BCMA_CORE_PCI_MDIO_BLK1_MGMT1, 0x7F64);
+		bcma_pcie_mdio_writeread(pc, BCMA_CORE_PCI_MDIO_BLK1,
+					 BCMA_CORE_PCI_MDIO_BLK1_MGMT3, data);
+	} else if (pc->core->id.rev >= 21 && pc->core->id.rev <= 22) {
+		data = up ? 0x75 : 0x7D;
+		bcma_pcie_mdio_writeread(pc, BCMA_CORE_PCI_MDIO_BLK1,
+					 BCMA_CORE_PCI_MDIO_BLK1_MGMT1, 0x7E65);
+		bcma_pcie_mdio_writeread(pc, BCMA_CORE_PCI_MDIO_BLK1,
+					 BCMA_CORE_PCI_MDIO_BLK1_MGMT3, data);
+	}
+}
+EXPORT_SYMBOL_GPL(bcma_core_pci_power_save);
+
+static void bcma_core_pci_extend_L1timer(struct bcma_drv_pci *pc, bool extend)
+{
+	u32 w;
+
+	w = bcma_pcie_read(pc, BCMA_CORE_PCI_DLLP_PMTHRESHREG);
+	if (extend)
+		w |= BCMA_CORE_PCI_ASPMTIMER_EXTEND;
+	else
+		w &= ~BCMA_CORE_PCI_ASPMTIMER_EXTEND;
+	bcma_pcie_write(pc, BCMA_CORE_PCI_DLLP_PMTHRESHREG, w);
+	bcma_pcie_read(pc, BCMA_CORE_PCI_DLLP_PMTHRESHREG);
+}
+
+void bcma_core_pci_up(struct bcma_drv_pci *pc)
+{
+	bcma_core_pci_extend_L1timer(pc, true);
+}
+
+void bcma_core_pci_down(struct bcma_drv_pci *pc)
+{
+	bcma_core_pci_extend_L1timer(pc, false);
+}