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, 147 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/bits.h b/drivers/usb/chipidea/bits.h
new file mode 100644
index 000000000..b1540ce93
--- /dev/null
+++ b/drivers/usb/chipidea/bits.h
@@ -0,0 +1,147 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * bits.h - register bits of the ChipIdea USB IP core
+ *
+ * Copyright (C) 2008 Chipidea - MIPS Technologies, Inc. All rights reserved.
+ *
+ * Author: David Lopo
+ */
+
+#ifndef __DRIVERS_USB_CHIPIDEA_BITS_H
+#define __DRIVERS_USB_CHIPIDEA_BITS_H
+
+#include <linux/usb/ehci_def.h>
+
+/*
+ * ID
+ * For 1.x revision, bit24 - bit31 are reserved
+ * For 2.x revision, bit25 - bit28 are 0x2
+ */
+#define TAG		      (0x1F << 16)
+#define REVISION	      (0xF << 21)
+#define VERSION		      (0xF << 25)
+#define CIVERSION	      (0x7 << 29)
+
+/* SBUSCFG */
+#define AHBBRST_MASK		0x7
+
+/* HCCPARAMS */
+#define HCCPARAMS_LEN         BIT(17)
+
+/* DCCPARAMS */
+#define DCCPARAMS_DEN         (0x1F << 0)
+#define DCCPARAMS_DC          BIT(7)
+#define DCCPARAMS_HC          BIT(8)
+
+/* TESTMODE */
+#define TESTMODE_FORCE        BIT(0)
+
+/* USBCMD */
+#define USBCMD_RS             BIT(0)
+#define USBCMD_RST            BIT(1)
+#define USBCMD_SUTW           BIT(13)
+#define USBCMD_ATDTW          BIT(14)
+
+/* USBSTS & USBINTR */
+#define USBi_UI               BIT(0)
+#define USBi_UEI              BIT(1)
+#define USBi_PCI              BIT(2)
+#define USBi_URI              BIT(6)
+#define USBi_SLI              BIT(8)
+
+/* DEVICEADDR */
+#define DEVICEADDR_USBADRA    BIT(24)
+#define DEVICEADDR_USBADR     (0x7FUL << 25)
+
+/* TTCTRL */
+#define TTCTRL_TTHA_MASK	(0x7fUL << 24)
+/* Set non-zero value for internal TT Hub address representation */
+#define TTCTRL_TTHA		(0x7fUL << 24)
+
+/* BURSTSIZE */
+#define RX_BURST_MASK		0xff
+#define TX_BURST_MASK		0xff00
+
+/* PORTSC */
+#define PORTSC_CCS            BIT(0)
+#define PORTSC_CSC            BIT(1)
+#define PORTSC_PEC            BIT(3)
+#define PORTSC_OCC            BIT(5)
+#define PORTSC_FPR            BIT(6)
+#define PORTSC_SUSP           BIT(7)
+#define PORTSC_HSP            BIT(9)
+#define PORTSC_PP             BIT(12)
+#define PORTSC_PTC            (0x0FUL << 16)
+#define PORTSC_WKCN           BIT(20)
+#define PORTSC_PHCD(d)	      ((d) ? BIT(22) : BIT(23))
+/* PTS and PTW for non lpm version only */
+#define PORTSC_PFSC           BIT(24)
+#define PORTSC_PTS(d)						\
+	(u32)((((d) & 0x3) << 30) | (((d) & 0x4) ? BIT(25) : 0))
+#define PORTSC_PTW            BIT(28)
+#define PORTSC_STS            BIT(29)
+
+#define PORTSC_W1C_BITS						\
+	(PORTSC_CSC | PORTSC_PEC | PORTSC_OCC)
+
+/* DEVLC */
+#define DEVLC_PFSC            BIT(23)
+#define DEVLC_PSPD            (0x03UL << 25)
+#define DEVLC_PSPD_HS         (0x02UL << 25)
+#define DEVLC_PTW             BIT(27)
+#define DEVLC_STS             BIT(28)
+#define DEVLC_PTS(d)          (u32)(((d) & 0x7) << 29)
+
+/* Encoding for DEVLC_PTS and PORTSC_PTS */
+#define PTS_UTMI              0
+#define PTS_ULPI              2
+#define PTS_SERIAL            3
+#define PTS_HSIC              4
+
+/* OTGSC */
+#define OTGSC_IDPU	      BIT(5)
+#define OTGSC_HADP	      BIT(6)
+#define OTGSC_HABA	      BIT(7)
+#define OTGSC_ID	      BIT(8)
+#define OTGSC_AVV	      BIT(9)
+#define OTGSC_ASV	      BIT(10)
+#define OTGSC_BSV	      BIT(11)
+#define OTGSC_BSE	      BIT(12)
+#define OTGSC_IDIS	      BIT(16)
+#define OTGSC_AVVIS	      BIT(17)
+#define OTGSC_ASVIS	      BIT(18)
+#define OTGSC_BSVIS	      BIT(19)
+#define OTGSC_BSEIS	      BIT(20)
+#define OTGSC_1MSIS	      BIT(21)
+#define OTGSC_DPIS	      BIT(22)
+#define OTGSC_IDIE	      BIT(24)
+#define OTGSC_AVVIE	      BIT(25)
+#define OTGSC_ASVIE	      BIT(26)
+#define OTGSC_BSVIE	      BIT(27)
+#define OTGSC_BSEIE	      BIT(28)
+#define OTGSC_1MSIE	      BIT(29)
+#define OTGSC_DPIE	      BIT(30)
+#define OTGSC_INT_EN_BITS	(OTGSC_IDIE | OTGSC_AVVIE | OTGSC_ASVIE \
+				| OTGSC_BSVIE | OTGSC_BSEIE | OTGSC_1MSIE \
+				| OTGSC_DPIE)
+#define OTGSC_INT_STATUS_BITS	(OTGSC_IDIS | OTGSC_AVVIS | OTGSC_ASVIS	\
+				| OTGSC_BSVIS | OTGSC_BSEIS | OTGSC_1MSIS \
+				| OTGSC_DPIS)
+
+/* USBMODE */
+#define USBMODE_CM            (0x03UL <<  0)
+#define USBMODE_CM_DC         (0x02UL <<  0)
+#define USBMODE_SLOM          BIT(3)
+#define USBMODE_CI_SDIS       BIT(4)
+
+/* ENDPTCTRL */
+#define ENDPTCTRL_RXS         BIT(0)
+#define ENDPTCTRL_RXT         (0x03UL <<  2)
+#define ENDPTCTRL_RXR         BIT(6)         /* reserved for port 0 */
+#define ENDPTCTRL_RXE         BIT(7)
+#define ENDPTCTRL_TXS         BIT(16)
+#define ENDPTCTRL_TXT         (0x03UL << 18)
+#define ENDPTCTRL_TXR         BIT(22)        /* reserved for port 0 */
+#define ENDPTCTRL_TXE         BIT(23)
+
+#endif /* __DRIVERS_USB_CHIPIDEA_BITS_H */